Annual Industry Reportpreviously “The State of Machine Translation”

The State of Translation Automation 2026

Published · Updated

AI translation quality depends on the language, the requirements and the workflow around the model. This report compares complete translation solutions—from AI models and MT engines to quality checks, repair and cooperating agents.

Why read the report:

  • See which solutions meet Basic, Standard and Advanced requirements in each language.
  • Compare how prompts, glossaries, quality checks and repair affect quality, cost and speed.
  • Understand where automated assessments are reliable and where the evidence is limited.

Evaluated AI models and MT engines

57 models from 37 vendors

Compare models

Evaluated solutions: a model plus its harness

We evaluate solutions — a model plus its harness: prompts, glossaries and other context, pre- and post-processing. The same engine with a glossary and without one is two solutions. Since we define quality as meeting requirements, we assess the absolute level of quality, and we increase solution complexity only when a simpler solution cannot meet all the requirements. This is how we build solutions for customers, and that is how we approach it in this report.

  1. 1Evaluated

    Off-the-shelf NMT

    A neural engine with default parameters and no glossary.

  2. 2Evaluated

    Adjusted NMT

    With glossaries, tone of voice, tag handling and other parameters supported by an API.

  3. 3Evaluated

    Off-the-shelf LLM

    An LLM with a simple translation prompt.

  4. 4Evaluated

    Adjusted LLM

    LLM with RAG for glossaries and prompt-tuning for tone of voice, tags and other requirements.

  5. 5Out of scope in 2026

    Fine-tuned models

    NMT domain adaptation and LLM fine-tuning in combination with other customization features.

  6. 6Evaluated

    Two-step solution

    Either NMT or LLM step, followed by an LLM-based automatic post-editing (APE) for missing requirements.

  7. 7Evaluated

    Multi-step

    More than two steps in one workflow to meet standard translation requirements: translate, then validate, then repair.

  8. 8Evaluated

    Multi-agent systems

    Agents responsible for different groups of requirements cooperate to meet all of them.

Explore translation workflows

Three levels of translation quality

We evaluate translation for three levels of translation quality, which altogether cover 10 requirements: general translation quality, tone of voice, terminology, gender neutrality, and six formatting requirements: tags, Unicode character integrity, locale conventions, HTML entities, valid JSON, and spacing at tag boundaries.

  1. 1Basic

    General translation quality — fluency, accuracy, completeness, evaluated using the MQM framework.

  2. 2Standard

    Basic + terminology, tone of voice, formatting, tag handling. Preferential requirements that most businesses have.

    In the 2026 benchmark: A glossary, formal tone of voice, HTML and JSON tag handling, Unicode.
  3. 3Advanced

    Standard + customer-specific context — style, idiomaticity, inclusivity, legal, compliance. Preferential requirements that some businesses have.

    In the 2026 benchmark: Gender neutrality.

Explore quality results

Key Takeaways for , , , and

Key takeaway 1 · Method

We assess solutions built from 57 AI models and MT engines against three levels of translation quality.

The 2026 State of Translation Automation measures the quality achievable in each target language. We evaluate solutions: a model plus its harness of prompts, glossaries and other context, pre- and post-processing.

The three quality levels define the requirements we check. Basic covers general translation quality. Standard adds terminology, tone of voice and six formatting requirements. Advanced adds gender neutrality.

The benchmark uses four English business texts totaling ~3,000 words and covers 100 target languages. We add complexity when a simpler solution does not meet the requirements.

Our Language engineers run the evaluation using Intento Language Hub. The same team of forward-deployed engineers implements production AI setups for 60+ enterprise customers across hundreds of language pairs.

37
vendors
57
models
229
model-and-harness configurations
3
quality levels
3,000
source words
100
target languages
Key takeaway 2 · Method

We measure which translation requirements solutions can meet in each language, and what it takes to meet them.

A metric score alone does not show which requirements a translation meets or what still needs improvement. We assess quality against the Basic, Standard and Advanced requirements, together with confidence in the assessment, solution complexity, cost and latency.

Key takeaway 3 · Method

We shortlist solutions with quality-estimation metrics, then assess them against translation requirements with Intento LQA.

Through the Intento Language Hub API, we obtain COMET-Kiwi and MetricX scores for language assessment and shortlisting. We use these two low-cost quality-estimation metrics to select 10 to 13 solutions per language for further assessment. They estimate accuracy and fluency, but do not check whether the translation meets terminology, tone-of-voice or gender-neutrality requirements.

A higher metric score does not always mean better compliance. In the glossary comparison, the COMET score fell in most cases where the translation used the approved terminology.

We then assess the shortlisted solutions against the 10 requirements grouped into Basic, Standard and Advanced, using Intento LQA. This automatic assessment combines LLM checks with checks in code.

Key takeaway 4 · Method

We assess general translation quality with three LLM judges and combine their findings with a fourth model.

We build the three LLM judges on Claude Opus 5, GPT-5.6 Sol and Gemini 3.1 Pro, using models from three vendors. Each judge receives the source sentence and its translation, without a reference translation, and identifies errors by type and severity using the MQM framework for classifying translation errors. We anonymize the three error lists before combining the findings with Claude Fable 5.

For gender-neutral translations, the LQA agent consults the gender-neutrality agent. We reassess findings on sentences that refer to a person against the relevant gender rule, so required neutral rewording does not count as a translation error.

Intento LQA assessment of general translation quality
Chart data
Intento LQA assessment of general translation quality
StepWhat it does
Source sentences and translations
Judge 1Claude Opus 5
Judge 2GPT-5.6 Sol
Judge 3Gemini 3.1 Pro
Judge agreementAt least 90% of segments
Combine findingsClaude Fable 5
Reassess errors in context
Consult the gender-neutrality agentFor gender-neutral translations
Weighted errors per 1,000 words
Key takeaway 5 · Method

We use LLM checks for four linguistic requirements and code to check the six formatting requirements.

We assess general translation quality with three LLM judges built on Claude Opus 5, GPT-5.6 Sol and Gemini 3.1 Pro, and combine their findings with Claude Fable 5. For tone of voice, terminology and gender neutrality, we use GPT-5.6 Sol to check each sentence where the requirement applies and Claude Opus 5, from another vendor, to review the findings.

The formatting checks cover tags, Unicode character integrity, locale conventions, HTML entities, valid JSON and spacing at tag boundaries. These checks give the same result for the same translation every time.

Assessment methods for the 10 translation requirements
Chart data
Assessment methods for the 10 translation requirements
StepWhat it does
General translation quality
Tone of voice
Terminology
Gender neutrality
Tags
Unicode character integrity
Locale conventions
HTML entities
Valid JSON
Spacing at tag boundaries
LLM assessmentThree judges; a fourth model combines findings
LLM assessmentOne model checks; another reviews
Checks in codeRepeatable rules
Key takeaway 6 · Method

We use the same English source texts across target languages so comparisons use the same source material.

The corpus covers four content types: an editorial article on thinking skills, a legal privacy notice for a loyalty program, an institutional mission statement and planning guide for an international education organization, and an operational travel-safety alert.

4
source texts
2,978
source words
100
target languages
Key takeaway 7 · Method

We accept an Intento LQA result only when the three LLM judges agree on at least 90% of sentences.

For each sentence, we take the most severe error each judge flags (none, minor, major or critical), and we count agreement when the three severity ratings are at most one level apart. Two judges can name the same error differently, so we compare severity only. The judges agree less where translations have more errors.

In 14 of the 96 languages, fewer than 50% of the shortlisted solutions pass this check, so we cannot assess quality there. These are Hausa, Igbo, Javanese, Kinyarwanda, Kurdish (Kurmanji), Malagasy, Scottish Gaelic, Sesotho, Shona, Somali, Wolof, Xhosa, Yoruba and Zulu, and in Igbo, Malagasy, Xhosa and Zulu no solution passes.

Shortlisted solutions meeting the judge-agreement threshold, by language
Chart data
Shortlisted solutions meeting the judge-agreement threshold, by language
LanguageShare of the solutions, %Intento LQA result
Igbo0Languages we cannot assess
Malagasy0Languages we cannot assess
Zulu0Languages we cannot assess
Xhosa0Languages we cannot assess
Sesotho8Languages we cannot assess
Wolof8Languages we cannot assess
Yoruba8Languages we cannot assess
Kinyarwanda9Languages we cannot assess
Shona9Languages we cannot assess
Somali9Languages we cannot assess
Javanese15Languages we cannot assess
Scottish Gaelic25Languages we cannot assess
Hausa27Languages we cannot assess
Kurdish (Kurmanji)33Languages we cannot assess
Cebuano50Languages we assess
Burmese55Languages we assess
Yiddish58Languages we assess
Icelandic62Languages we assess
Frisian69Languages we assess
Swahili73Languages we assess
Tatar73Languages we assess
Kyrgyz73Languages we assess
Uzbek73Languages we assess
Assamese73Languages we assess
Sundanese75Languages we assess
Kazakh75Languages we assess
Khmer75Languages we assess
Mongolian80Languages we assess
Pashto80Languages we assess
Azerbaijani82Languages we assess
Malay82Languages we assess
Basque83Languages we assess
Irish83Languages we assess
Lithuanian83Languages we assess
Sinhala83Languages we assess
Japanese85Languages we assess
Georgian91Languages we assess
Lao91Languages we assess
Odia (Oriya)91Languages we assess
Armenian91Languages we assess
Nepali91Languages we assess
Portuguese (European)91Languages we assess
Tajik92Languages we assess
Hebrew92Languages we assess
Gujarati92Languages we assess
Thai92Languages we assess
Danish92Languages we assess
Chinese Traditional92Languages we assess
Amharic100Languages we assess
Kannada100Languages we assess
Marathi100Languages we assess
Welsh100Languages we assess
German100Languages we assess
Malayalam100Languages we assess
Telugu100Languages we assess
Arabic (MSA)100Languages we assess
Belarusian100Languages we assess
Spanish (European)100Languages we assess
Tagalog100Languages we assess
Turkish100Languages we assess
Hungarian100Languages we assess
Vietnamese100Languages we assess
Estonian100Languages we assess
Indonesian100Languages we assess
Macedonian100Languages we assess
Punjabi100Languages we assess
Tamil100Languages we assess
Ukrainian100Languages we assess
Chinese Simplified100Languages we assess
Polish100Languages we assess
Romanian100Languages we assess
Urdu100Languages we assess
Bengali100Languages we assess
Catalan100Languages we assess
Farsi100Languages we assess
Finnish100Languages we assess
Galician100Languages we assess
Hindi100Languages we assess
Italian100Languages we assess
Korean100Languages we assess
Latvian100Languages we assess
Dutch100Languages we assess
Russian100Languages we assess
Albanian100Languages we assess
Serbian100Languages we assess
Swedish100Languages we assess
Norwegian100Languages we assess
Bulgarian100Languages we assess
Croatian100Languages we assess
Slovak100Languages we assess
Afrikaans100Languages we assess
Bosnian100Languages we assess
Czech100Languages we assess
Slovenian100Languages we assess
Greek100Languages we assess
French100Languages we assess
Key takeaway 8 · Method

We reassess major and critical errors in context, and ~one in three becomes a minor error or no error.

We assess translations with LLM judges one sentence at a time, so the judges count as errors a pronoun or a tense that depends on the previous sentence, content moved across a sentence boundary, or a heading translated as a noun phrase. We send each major and critical error to Claude Fable 5 with the two sentences before and the one after, in the source and in the translation, and ask whether the error still stands. We downgrade most of the changed errors to minor and drop the rest, and we keep nearly every critical error as critical.

Nearly all solutions that reach the limit of three major errors in the four texts only after reassessment use LLMs. Most MT engine translations remain above that limit. Claude Fable 5 is also one of the models we evaluate, and the re-check changes errors in its own translations as often as in those of the other leading LLMs.

Major and critical errors after reassessment in context, by source text
Chart data
Major and critical errors after reassessment in context, by source text
TextKept, %Downgraded to minor, %Dropped, %
Editorial article602911
Education guide71218
Travel alert (JSON)78139
Privacy notice74224
Key takeaway 9 · Method

In our tests, examples in the prompts reduced LLM-judge agreement, so we use prompts without examples.

We assess each translation with three LLM judges, built on Claude Opus 5, GPT-5.6 Sol and Gemini 3.1 Pro. We tested one set of examples for all languages and one set per language on translations into Spanish and Ukrainian from the 2025 edition of the benchmark, which was assessed by human reviewers.

With the set for all languages, the Gemini 3.1 Pro judge flagged an error in 7% of the sentences, against 36% without examples, while the two other judges barely changed, and we saw the same drop when we repeated the test twice on translations from 2026. Of the Ukrainian sentences where human reviewers marked a major or critical error, the three judges agreed on such an error in 6% with the set for all languages, against 46% without examples.

In one of the examples, an English term left untranslated in a Chinese translation was a minor error. With this example in the prompt, the judges also rated an English term left untranslated in a Ukrainian translation as minor, while human reviewers rated it as major. We rely on the agreement of the three judges rather than on human ratings, because in the 2025 human review, reviewers rated severity inconsistently across languages, and sometimes within one language.

Key takeaway 10 · Method

We found no consistent vendor preference in the LQA judges based on Gemini 3.1 Pro, GPT-5.6 Sol and Claude Opus 5.

Intento LQA scores translations with a panel of three LLM judges: Gemini 3.1 Pro, GPT-5.6 Sol and Claude Opus 5. Each judge is itself a solution, a model in a harness that scores translations.

Two of the three judge models also appear as translation solutions in the shortlist, so we tested whether a judge scores translations from its own vendor higher. For every scored solution we compared each judge with the average of the three, separately for solutions from the same vendor as the judge and for all others. The same-vendor difference is below 0.2 points on the 0–100 general translation quality score and goes in different directions for different judges, so we found no consistent vendor preference in this test.

The same test showed that the judges differ in strictness. Claude Opus 5, the strictest judge, scores 2.7 points below Gemini 3.1 Pro, the most lenient one, while the best and worst shortlisted solutions in a language differ by about 12 points. A judge that is strict or lenient across the board does not change the order of solutions within a language, because every judge scores every solution. Absolute scores do depend on which judges sit on the panel, so we keep the same panel for the whole 2026 edition.

Score difference for each judge relative to the other two
Chart data
Score difference for each judge relative to the other two
JudgeSeverity offset, points above or below the other two judges
Gemini 3.1 Pro1.3
GPT-5.6 Sol0.13
Claude Opus 5-1.44
Key takeaway 11 · Models

The best open-weight LLM translation has more errors than the best other LLM translation in all 50 languages with results for both.

The median ratio is ~2.9 times as many errors in the best open-weight LLM translation.

The gap is smallest in Indonesian, where Google Gemma 4 has the only open-weight solution that meets general translation quality (no critical error, at most three major errors and at most 20 weighted errors per 1,000 words), and it meets every other Standard requirement too. The open-weight LLMs on our shortlists are Google Gemma 4, OpenAI gpt-oss-120b, Meta Llama 4 Maverick, Alibaba Qwen3-235B-A22B and Swiss AI Apertus-8B.

Errors in the best open-weight and other LLM solutions, by language
Chart data
Errors in the best open-weight and other LLM solutions, by language
LanguageOpen-weight LLM with the fewest errorsBest open-weight LLM, weighted errors per 1,000 wordsOther LLM with the fewest errorsBest other LLM, weighted errors per 1,000 words
IndonesianGoogle Gemma 417.8Google Gemini 3.1 Pro Preview12.5
SwahiliGoogle Gemma 454.7Anthropic Claude Fable 536.3
TagalogGoogle Gemma 435.9OpenAI GPT-5.6 Terra21.4
CebuanoGoogle Gemma 461.3Google Gemini 3.1 Pro Preview34.9
KoreanGoogle Gemma 440.5OpenAI GPT-5.6 Terra21.4
RussianGoogle Gemma 424.7Anthropic Claude Fable 512.9
SerbianGoogle Gemma 437.2Anthropic Claude Fable 517.8
AfrikaansGoogle Gemma 463.9OpenAI GPT-5.528.7
HindiGoogle Gemma 426.4Anthropic Claude Fable 511.5
TurkishGoogle Gemma 428.3Anthropic Claude Fable 512.2
DutchOpenAI gpt-oss-120b33.9OpenAI GPT-5.514.5
GujaratiGoogle Gemma 445.2Anthropic Claude Fable 518.8
Chinese SimplifiedOpenAI gpt-oss-120b54.4OpenAI GPT-5.6 Terra22.7
FrenchOpenAI gpt-oss-120b54.1Anthropic Claude Fable 522.1
FarsiGoogle Gemma 432Google Gemini 3.1 Pro Preview12.9
UrduGoogle Gemma 445.8Anthropic Claude Fable 518.5
KannadaGoogle Gemma 459.3OpenAI GPT-5.6 Terra23.7
ThaiGoogle Gemma 449.8Anthropic Claude Opus 4.819.8
NorwegianGoogle Gemma 425OpenAI GPT-5.59.9
ItalianGoogle Gemma 428.7OpenAI GPT-5.511.2
VietnameseGoogle Gemma 435.3Anthropic Claude Opus 4.813.8
BosnianGoogle Gemma 446.1Google Gemini 3.1 Pro Preview17.5
Arabic (MSA)Google Gemma 443.2OpenAI GPT-5.516.2
SundaneseOpenAI gpt-oss-120b97.9OpenAI GPT-5.535.3
AlbanianGoogle Gemma 451.7Anthropic Claude Fable 518.1
UkrainianGoogle Gemma 428.3Anthropic Claude Fable 59.9
KhmerGoogle Gemma 453.4OpenAI GPT-5.6 Sol18.5
MalayalamGoogle Gemma 451.7OpenAI GPT-5.6 Sol16.8
Portuguese (European)Meta Llama 4 Maverick46.1Anthropic Claude Fable 514.8
AssameseGoogle Gemma 495.6OpenAI GPT-5.530.3
PolishGoogle Gemma 443.5OpenAI GPT-5.6 Terra13.5
MarathiGoogle Gemma 454.4OpenAI GPT-5.6 Sol16.2
AzerbaijaniGoogle Gemma 456OpenAI GPT-5.516.5
Odia (Oriya)Google Gemma 479.1OpenAI GPT-5.6 Luna23.1
BengaliGoogle Gemma 459OpenAI GPT-5.517.1
GermanMeta Llama 4 Maverick36.9Google Gemini 3.1 Pro Preview10.5
SinhalaGoogle Gemma 460Anthropic Claude Fable 517.1
MacedonianGoogle Gemma 442.8OpenAI GPT-5.6 Terra11.9
CatalanOpenAI gpt-oss-120b46.8Google Gemini 3.1 Pro Preview11.9
MalayOpenAI gpt-oss-120b43.5OpenAI GPT-5.510.9
PunjabiGoogle Gemma 469.9OpenAI GPT-5.6 Sol16.8
AmharicGoogle Gemma 4104.5OpenAI GPT-5.6 Sol23.1
HebrewOpenAI gpt-oss-120b75.8Anthropic Claude Fable 516.5
TeluguGoogle Gemma 467.6Anthropic Claude Fable 514.5
CroatianGoogle Gemma 447.8OpenAI GPT-5.59.6
BulgarianOpenAI gpt-oss-120b63.3Google Gemini 3.1 Pro Preview11.2
TamilGoogle Gemma 465.6OpenAI GPT-5.6 Sol10.5
TatarOpenAI gpt-oss-120b206Google Gemini 3.1 Pro Preview30
PashtoOpenAI gpt-oss-120b182.6OpenAI GPT-5.6 Sol26.4
WelshOpenAI gpt-oss-120b189.5Google Gemini 3.1 Pro Preview12.9
Key takeaway 12 · Models

Some translation errors and unmet requirements recur across languages for the same model.

The translated JSON document is invalid in every language for Translated Lara 2, Microsoft Translator, Google Translation LLM and Widn AI Tower Sugarloaf. Translations of the JSON document from Anthropic Claude Opus 4.8 meet the tag handling requirement in 12 of 46 languages, against 73 of 76 languages for Google Gemini 3.1 Pro Preview in every document.

Translations from Translated Lara 2 carry an HTML code in place of each newline character between the tags and the JSON fields of the source file, in every language. Without these codes, the translated JSON document would be valid in 36 of the 44 languages. In nearly every language, translations from Google Translation LLM carry additions (sentences that are not in the source).

We translate every text with its HTML tags and set the format parameter for tagged content where the API has one, textType html for Microsoft Translator, mimeType text/html for Google Translation LLM and content_type text/html for Translated Lara 2. We don't set a format parameter for Widn AI Tower Sugarloaf.

Share of one-step solutions meeting the tag handling and formatting requirements, by model
Chart data
Share of one-step solutions meeting the tag handling and formatting requirements, by model
ModelTag handling, %Formatting, %
Google Gemini 3.1 Pro Preview96%87%
Google Gemini 3.5 Flash56%90%
OpenAI GPT-5.589%76%
Anthropic Claude Fable 568%95%
DeepL Next Gen (off the shelf)0%0%
Anthropic Claude Opus 4.824%91%
OpenAI GPT-4.171%98%
Translated Lara 270%0%
Google Gemma 430%78%
Anthropic Claude Sonnet 531%86%
GLM-588%91%
OpenAI GPT-5.6 Sol61%97%
Microsoft Translator (off the shelf)0%0%
Anthropic Claude Sonnet 4.619%68%
Google Translation LLM (adjusted)0%0%
Mistral Large 336%43%
OpenAI GPT-5.6 Luna46%85%
Cohere Command A (command-a-translate-08-2025)27%91%
OpenAI GPT-5.6 Terra80%85%
Grok 4.20 (reasoning)38%88%
DeepL Next Gen (adjusted)0%13%
DeepSeek V3.257%93%
MoonshotAI Kimi K2.542%25%
OpenAI gpt-oss-120b42%83%
Key takeaway 13 · Models

We verify language support by checking whether each model returns a usable translation in that language.

Vendor documentation does not reliably say which languages a model supports. LLMs have no language list, and when we tested the language lists of MT vendors, they were wrong in both directions: we did not get a translation in some listed languages, and got translations in some unlisted ones.

From 21 of the 57 models, in 94 of the 100 languages, we got text in the wrong language, garbage or a near-empty output, a translation cut off part-way, text in the wrong script, or text far shorter than the source. We remove such outputs before scoring quality, because a quality score for a text that is not a translation means nothing. A model supports a language only when we got a translation in it from the model, and that is how we determine language support for every model in the report.

Language support by model
Chart data
Language support by model
ModelSupported language, languagesNominally supported language, languages
Anthropic Claude Fable 51000
Anthropic Claude Opus 4.81000
Anthropic Claude Sonnet 4.61000
Anthropic Claude Sonnet 51000
DeepSeek V3.21000
GLM-51000
Google Gemini 3.1 Pro Preview1000
Google Gemini 3.5 Flash1000
Google Gemma 41000
Grok 4.20 (non-reasoning)1000
Grok 4.20 (reasoning)1000
Mistral Large 31000
Mistral Medium 3.11000
MoonshotAI Kimi K2.51000
OpenAI GPT-4.11000
OpenAI GPT-5.51000
OpenAI GPT-5.6 Luna1000
OpenAI GPT-5.6 Sol1000
OpenAI GPT-5.6 Terra1000
Anthropic Claude Haiku 4.5991
Google Cloud Advanced Translation API981
M2.5982
OpenAI gpt-oss-120b982
Translated Lara 2970
Cohere Command A (command-a-translate-08-2025)955
ModernMT Enterprise Edition930
Microsoft Translator891
DeepL Next Gen841
Apertus-8B-25098317
Yandex830
Alibaba Cloud Qwen3-235B-A22B790
Google Translation LLM791
Alibaba771
Amazon690
Cohere Tiny Aya681
AI21 Jamba Large 1.76535
SYSTRAN PNMT API570
AppTek NMT540
Tilde283
Supertext Supertext LLM260
NiuTrans220
Pangeanic220
Widn AI Tower Sugarloaf220
Oracle210
Tencent Cloud TMT130
Baidu120
Meta Llama 4 Maverick110
Naver Papago NMT Commercial110
SpeakLeash Bielik-11B-v3.0-Instruct1119
Widn AI Tower Anthill1127
Youdao82
TartuNLP70
ALL-Lab68
iFlyTek MT60
Elia Elhuyar Machine Translation System50
Widn AI Tower Vesuvius236
Tarjama10
Key takeaway 14 · Models

Vendor rules for access, billing, region and request size can affect translation cost.

The rules fall into four kinds: access (keys, trials, licenses), billing and quota (prepaid balances, character quotas, minimum charges), region (endpoints and resources bound to one region) and request limits (parameters and request sizes). Some vendors have a minimum charge per request (5,000-20,000 characters), which raises the cost of short texts. During this benchmark we use Intento Language Hub, which provides a single API to all NMT and LLM models and handles differences in how the APIs express translation requests.

Key takeaway 15 · Models

We use zero data retention wherever the model API supports it.

Zero data retention means the vendor does not store the requests sent to its API, under the applicable retention terms. For enterprise translation this matters because the content is often confidential, and the texts in this benchmark are enterprise content, contributed on our promise to use them for evaluation only, never for training.

The API of Claude Fable 5 returns an error unless the account has data retention turned on, so we translate with it in a dedicated workspace. The workspace has its own API key and keeps requests for 30 days, and we use it only for the benchmark texts.

Key takeaway 16 · Harnesses

General translation quality improves mainly in three-step solutions (translation + LQA + repair), while most translations meet the other Standard requirements in two-step solutions (translation + post-edit) already.

In a two-step solution, we post-edit the one-step translation with an LLM, using a prompt for the requirement it falls short on, and repair tags and formatting by code. In a three-step solution, we assess the translation with Intento LQA and send it with the findings to an LLM for a repair. In most solutions, we post-edit or repair with the model we translated the text with. We implement these two-step and three-step workflows in Intento Language Hub, including the transfer of Intento LQA findings to the repair step.

On the same solutions, weighted errors fall from 36 per 1,000 words in the one-step solutions to 28 in the two-step solutions and to 16 in the three-step solutions. General translation quality comes mostly from the pre-training of a model, and we see little gain from a second pass without a list of the errors.

Where only tone of voice or terminology fell short, 90% of the two-step solutions met every requirement, and where only tags or formatting fell short, ~80% did, with tags and formatting repaired by code. Three-step solutions meet these requirements about as often. We assess every two-step and three-step solution again, without the findings in the prompts of the LQA judges.

Requirements missed per 1,000 words in one-step, two-step and three-step solutions
Chart data
Requirements missed per 1,000 words in one-step, two-step and three-step solutions
RequirementOne-step solutionsTwo-step solutions (translation + post-edit)Three-step solutions (translation + LQA + repair)
General translation quality36.127.515.8
Tone of voice0.70.30
Tag handling1.30.70
Formatting0.300
Key takeaway 17 · Harnesses

~82% of the three-step solutions (translation + LQA + repair) still meet every requirement met by the one-step solution, and the others most often miss terminology or tone of voice.

A solution meets general translation quality with no critical error, at most three major errors and at most 20 weighted errors per 1,000 words. Of the three-step solutions that meet it but not every other requirement, 25% still meet every requirement met by the one-step solution.

In the languages with a glossary, 58% of the three-step solutions meet the terminology requirement, against 88% of the one-step solutions they are built on. Most of the terms missing in the three-step solutions are paraphrased. ~5% of the three-step solutions have a critical error the one-step solution did not have. We check every requirement again in every three-step solution.

Key takeaway 18 · Harnesses

Gender-neutral versions of the best solutions lose less accuracy with the gender-neutrality agent involved at all stages of the solution, including post-editing, LQA and repair, than with the agent involved in the translation step only.

Rewording for gender neutrality changes the meaning of some sentences, and Intento LQA counts those changes as errors. With the gender-neutrality agent involved in the translation step only, 39% of the gender-neutral versions still met every Standard requirement. With the agent involved at all stages of the solution, including post-editing, LQA and repair, 85% did.

Of the gender-neutral versions that still fell short, 16% met the Advanced requirements as two-step solutions (translation + post-edit), and 46% of the rest as three-step solutions (translation + LQA + repair), with the gender findings.

We use Intento Language Hub to coordinate the gender-neutrality agent with translation, post-editing, LQA and repair, using the same language-specific gender rule throughout.

Gender-neutral versions still meeting every Standard requirement
Chart data
Gender-neutral versions still meeting every Standard requirement
Gender-neutrality agentStill meet every Standard requirement, %Fall short, %
Agent in the translation step only3961
Agent at all stages, including post-editing, LQA and repair8515
Key takeaway 19 · Harnesses

13 of the 28 MT engines support a glossary and 8 support tone of voice through their API, and 14 support neither.

An MT engine takes the Standard requirements only through its API, if the model supports them. We upload a glossary in advance and reference it in each request, send the terms found in each segment with the request, or put those terms into a free-text instructions field.

Tone values differ by engine: formal, natural, expressive or precise at ALL-Lab, politeness as more or less at Supertext, formality as more, less, prefer_more or prefer_less at DeepL Next Gen. Naver accepts tone only in Korean and Japanese, DeepL Next Gen in 13 languages and Supertext in 26.

Key takeaway 20 · Harnesses

We run a dedicated test for each of three types of glossary support, because advertised support is not always present, often comes with limits, and can fail without an error.

"Supports glossaries" means one of three things across the models we tested: terms inserted into the prompt, a glossary uploaded in advance, or a dynamic glossary sent with each request. For a model with glossary support in a language, we benchmark two translations: a baseline, and one adjusted with the glossary and the other Standard requirements. For a model without glossary support in a language, we stop at the baseline. In both cases, we then try to improve the best results further by adding workflow steps.

Key takeaway 21 · Harnesses

Sending a glossary to an MT engine does not guarantee its use, so we test it with texts that must change when the glossary applies.

MT engines accept a glossary through the API and report success. Often the translation does not change, and the API response does not show it. So we built a test set that contains the glossary terms. We translate it with the glossary and without it, and count the approved terms in each result. In 2026 the test set has 46 terms in 16 languages.

It caught three mistakes on our side that any integration can make. A glossary created for Google Cloud Advanced Translation does not apply to Google Translation LLM, although both sit behind one API. ModernMT imports a glossary in the background, and the id it returns is empty until the import completes. Yandex takes the glossary only inside each request, not as an uploaded resource.

The test set also showed where engines do not apply a glossary at all: Yandex rejects it for Belarusian, Ukrainian and Serbian, Google Translation LLM rejects it for Serbian in Latin script, and ModernMT ignores it for Arabic.

Key takeaway 22 · Harnesses

We use one prompt template for all 100 languages, with three parameters (the target language and its script, the tone instruction and the glossary terms in the segment).

There are two templates: a short one for the Basic quality level and a longer one for the Standard level. We name the script where models diverge: Latin for Serbian and Bosnian, Cyrillic for Kazakh, Hebrew script for Yiddish, Kurmanji for Kurdish. The tone instruction stays the same across a language. We match the glossary terms per segment. NMT models do not support prompts, so we pass the glossary and the tone of voice through API parameters, if the model supports them.

For requests with context, we use Intento Language Hub to retrieve the relevant glossary terms and language-specific tone instructions for the prompt.

Key takeaway 23 · Languages

We measure the cost, time and complexity of meeting each set of quality requirements with a main solution and a backup.

We seek a main solution and a backup that both meet the requirements. At least one is a simple, one-step solution in 54 of the 100 languages for Basic requirements, 38 for Standard and 13 for Advanced. The backup may need more steps.

At least two solutions qualify, but none is one-step, in another 25 languages for Basic, 40 for Standard and 40 for Advanced. In 18 languages, we cannot assess all the requirements. For each language and quality level, we also report errors, cost and time for the same qualifying solution, selected by quality, cost or latency in the chart settings.

We implement the candidate solutions in Intento Language Hub and compare the quality, cost and time needed to meet the requirements in each language.

Languages by the number of solutions meeting each set of requirements
Chart data
Languages by the number of solutions meeting each set of requirements
Quality levelSimple solution + backup, languagesTwo or more solutions, none simple, languagesOne solution, languagesNo solution, languagesCannot assess, languages
Basic54251218
Standard38402218
Advanced1340181118
Intento
Key takeaway 24 · Languages

Five language tiers show how many solutions qualify and whether any qualifying solution is one-step.

We aim to identify at least two solutions that meet every requirement of a quality level: a main solution and a backup.

Tier 1: simple solution + backup. At least two solutions qualify, and at least one is one-step. This usually leaves scope to choose based on quality, cost or time.

Tier 2: two or more solutions, none simple. At least two qualify, but all need additional steps: translation + post-edit, translation + LQA + repair, or, for gender neutrality, the gender-neutrality agent. There may still be scope to optimize, but most options are slow, expensive or both.

Tier 3: one solution. Only one solution meets every requirement.

Tier 4: no solution. None of the assessed solutions meets every requirement, including the three-step and multi-agent solutions. In practice, complex bespoke workflows can achieve high quality in these languages, sometimes reaching 9+ steps for Standard requirements. These workflows are outside the scope of this report.

Tier 5: cannot assess. The automatic metrics or Intento LQA cannot assess quality.

Errors, cost and time by language tier, for each quality level
Chart data
Errors, cost and time by language tier, for each quality level
Quality levelTierLanguagesTotal errors per 1,000 words, medianTotal errors per 1,000 words, 25th percentileTotal errors per 1,000 words, 75th percentileCost per million characters, median, US$Cost per million characters, 25th percentileCost per million characters, 75th percentileSeconds per 1,000 words, medianSeconds per 1,000 words, 25th percentileSeconds per 1,000 words, 75th percentile
BasicTier 1: simple solution + backup54151319$27$10$4167562206
BasicTier 2: two or more solutions, none simple2511914$589$570$617298240320
BasicTier 3: one solution1191919$562$562$562203203203
BasicTier 4: no solution2201722$659$647$670458351566
StandardTier 1: simple solution + backup38151318$11$7$29686296
StandardTier 2: two or more solutions, none simple40121015$577$552$604262205318
StandardTier 3: one solution2181719$561$561$562242223261
StandardTier 4: no solution2201722$659$647$670458351566
AdvancedTier 1: simple solution + backup13121214$10$10$17675476
AdvancedTier 2: two or more solutions, none simple4010812$620$556$982252203316
AdvancedTier 3: one solution18131217$966$31$1,022210137273
AdvancedTier 4: no solution1112918$991$910$1,040239194302
Optimize forQualityCostLatency

In each cell: the languages of the tier, and over them the median total errors per 1,000 words (EPT) across all requirements, the median seconds per 1,000 words and the median cost per million characters of the solution selected under Optimize for in each language, with the distance to the 25th and 75th percentiles in small type. Where no solution meets the selected requirements, the values of the best available solution.

Tier 1: simple solution + backupTier 2: two or more solutions, none simpleTier 3: one solutionTier 4: no solutionTier 5: cannot assessBasic requirements
54 languagesTier 115.4 EPT+3.9−2.875 sec+131−13$27/1M+$388−$18
25 languagesTier 211.2 EPT+2.4−2.6298 sec+22−58$589/1M+$29−$18
1 languageTier 319.1 EPT+0.0−0.0203 sec+0−0$562/1M+$0.00−$0.00
2 languagesTier 419.5 EPT+2.3−2.3458 sec+108−108$659/1M+$11−$11
18 languagesTier 5cannot assess
Standard requirements
38 languagesTier 115.3 EPT+2.3−2.068 sec+28−6$11/1M+$18−$4.45
40 languagesTier 211.8 EPT+3.3−1.5262 sec+56−57$577/1M+$27−$25
2 languagesTier 318.0 EPT+0.6−0.6242 sec+19−19$561/1M+$0.44−$0.44
2 languagesTier 419.5 EPT+2.3−2.3458 sec+108−108$659/1M+$11−$11
18 languagesTier 5cannot assess
Advanced requirements
13 languagesTier 112.5 EPT+1.3−0.367 sec+9−13$10/1M+$6.47−$0.52
40 languagesTier 29.8 EPT+2.2−1.9252 sec+64−49$620/1M+$361−$64
18 languagesTier 313.4 EPT+3.9−1.4210 sec+63−73$966/1M+$55−$935
11 languagesTier 411.8 EPT+6.1−2.5239 sec+62−45$991/1M+$49−$81
18 languagesTier 5cannot assess
Intento
Key takeaway 25 · Languages

No low-resource language has a simple solution with a backup for the Basic requirements, and 5 of 40 high-resource languages also need more steps.

The five high-resource languages are Chinese Simplified and Traditional, French, Japanese and Korean.

Languages in the same family often share a tier. All 12 Slavic languages are in tier 1 for Basic. The Uralic languages (Estonian, Finnish, Hungarian) are in tier 1 for Basic and Standard. The Dravidian languages (Kannada, Malayalam, Tamil, Telugu) are in tier 2 for Standard and Advanced.

All 18 languages we cannot assess are low-resource or medium-resource languages.

Language tiers for the Basic requirements, by resource level
Chart data
Language tiers for the Basic requirements, by resource level
Resource levelTier 1: simple solution + backup, languagesTier 2: two or more solutions, none simple, languagesTier 3: one solution, languagesTier 4: no solution, languagesTier 5: cannot assess, languages
High-resource languages (40)355000
Medium-resource languages (35)1910114
Low-resource languages (25)0100114
Key takeaway 26 · Languages

In 13 languages, full gender neutrality requires rewording because forms of address or verb agreement have no neutral alternative.

In Hindi, Urdu, Punjabi and Gujarati, the verb agrees with the gender of the person, also with the polite form of you. In Croatian, Serbian, Bosnian, Slovenian, Czech, Polish and Lithuanian, past-tense forms and participles carry gender after the polite you or the authorial we. In Arabic and Hebrew, all forms of address are masculine or feminine. We assess these languages against the same gender rule as every other language, and in 12 of them at most one of the two best solutions is fully gender-neutral.

Key takeaway 27 · Quality

We set pass-or-fail thresholds for nine requirements and report locale conventions as advisory.

For general translation quality, we weight every error by severity, 1 for a minor error, 5 for a major and 10 for a critical, and a translation meets the bar with no critical error, at most three major errors in the four texts and at most 20 weighted errors per 1,000 words. That leaves room for up to 60 minor errors in the ~3,000 words.

We set 100% for the other Standard requirements, because we check each one as met or not met, by code for the formatting requirements and sentence by sentence for tone of voice and terminology, and because a broken tag or an invalid JSON document can stop a translation from being imported or displayed correctly.

Terminology applies in the 16 languages with a glossary, and Unicode character integrity includes look-alike letters from another script. We report locale conventions as a share without a bar, because whether to localize punctuation is a matter of house style. For gender neutrality (Advanced), we also require 100% of the sentences that refer to a person.

Thresholds for the requirements at each quality level
Chart data
Thresholds for the requirements at each quality level
Quality levelRequirementBar
BasicGeneral translation qualityNo critical error, at most 3 major errors and at most 20 weighted errors per 1,000 words
StandardTerminology100%, in the 16 languages with a glossary
StandardTone of voice100%
StandardTags100%
StandardUnicode character integrity100%, including look-alike letters from another script
StandardLocale conventionsNo bar, reported as a share
StandardHTML entities100%
StandardValid JSON100%
StandardSpacing at tag boundaries100%
AdvancedGender neutrality100% of the sentences that refer to a person
Key takeaway 28 · Quality

Fewer than two solutions meet Basic requirements in 3 of 82 languages, Standard in 4 and Advanced in 29.

For Basic requirements, Afrikaans has one qualifying solution; Burmese and Sundanese have none.

For Standard requirements, Afrikaans and Frisian have one qualifying solution each; Burmese and Sundanese have none.

For Advanced requirements, 11 languages have no qualifying solution: Albanian, Arabic, Burmese, Czech, French, Hebrew, Polish, Sinhala, Sundanese, Urdu and Yiddish. The other 18 languages that fall short of two qualifying solutions have one each.

Languages by the number of solutions meeting each set of quality requirements
Chart data
Languages by the number of solutions meeting each set of quality requirements
LevelTwo or more solutions, languagesOne solution, languagesNo solution, languages
Basic7912
Standard7822
Advanced531811
Key takeaway 29 · Quality

Accuracy errors account for 60% of severity-weighted translation errors, including 38% from mistranslation.

Fluency errors account for 36% of severity-weighted translation errors.

Accuracy errors are mistranslation, omission, addition, under- and over-translation and untranslated text, and fluency errors are grammar, spelling and punctuation. Grammar is the second largest type, at 20%, and the other 4% are broken characters, stray markup and corrupted output.

General translation quality errors by type
Chart data
General translation quality errors by type
Error typeShare of the weighted errors, %Group
Mistranslation38.1Accuracy
Grammar19.8Fluency
Punctuation9.4Fluency
Addition7.1Accuracy
Omission6.9Accuracy
Spelling6.6Fluency
Untranslated text2.8Accuracy
Under-translation2.7Accuracy
Over-translation2Accuracy
Character encoding1.7Broken characters or markup
Stray markup1.6Broken characters or markup
Corrupted output1.1Broken characters or markup
Culture-specific reference0.2Accuracy
Key takeaway 30 · Quality

LLM translations meet general translation quality requirements in 21% of cases, while MT engine translations almost never do.

Among the evaluated LLM solutions that initially fall short, 24% meet this requirement after two steps and 60% after three. General translation quality covers translation errors of every type, such as mistranslations, omissions and grammar errors, which we classify by type and severity following MQM, the industry standard for classifying translation errors.

A solution meets it with no critical error, at most three major errors and at most 20 weighted errors per 1,000 words in the four texts (minor 1, major 5, critical 10). Translations from OpenAI GPT-5.6 Sol meet it in 20 of the 32 languages where we shortlisted them and from Anthropic Claude Fable 5 in 33, and among MT engines only translations from DeepL Next Gen do, in German and Romanian.

In 28 languages, among them French, Japanese and Korean, every one-step solution misses it. Where an LLM solution misses it, the median goes from 36 weighted errors per 1,000 words to 28 in the two-step solution and to 16 in the three-step solution, below the bar. We evaluated these repairs on LLM solutions. MT engine solutions fell short on too many requirements to enter this repair comparison.

Weighted errors per 1,000 words of one-step solutions, median by model
Chart data
Weighted errors per 1,000 words of one-step solutions, median by model
ModelWeighted errors per 1,000 words of one-step solutions, medianType
OpenAI GPT-5.6 Sol18.6LLMs
Anthropic Claude Fable 519.4LLMs
OpenAI GPT-5.6 Terra20.6LLMs
OpenAI GPT-5.522.1LLMs
Anthropic Claude Opus 4.824.4LLMs
Google Gemini 3.1 Pro Preview25LLMs
OpenAI GPT-5.6 Luna28.9LLMs
Cohere Command A Translate33.2LLMs
Anthropic Claude Sonnet 535.3LLMs
Anthropic Claude Sonnet 4.635.6LLMs
Google Gemini 3.5 Flash35.9LLMs
MoonshotAI Kimi K2.536.6LLMs
Translated Lara 238.2LLM-based MT engines
OpenAI GPT-4.138.2LLMs
xAI Grok 4.20 (reasoning)41.2LLMs
DeepL Next Gen41.9LLM-based MT engines
z.ai GLM-543.2LLMs
Mistral Large 345.3LLMs
Google Gemma 447.8Open-weight LLMs
DeepSeek V3.252.2LLMs
OpenAI gpt-oss-120b58.8Open-weight LLMs
Widn AI Tower Sugarloaf60.2LLM-based MT engines
xAI Grok 4.20 (non-reasoning)65.6LLMs
Microsoft Translator67.9MT engines
Google Translation LLM81.9LLM-based MT engines
Key takeaway 31 · Quality

LLM translations meet glossary requirements more often than MT engine translations, and additional steps can correct terminology errors.

Terminology requires the approved translation of every glossary term, in any of its correct forms.

In the 16 languages with a glossary, translations from LLMs have terminology errors in 43% of the cases, translations from LLM-based MT engines in 68% and translations from other MT engines in every case. Translations from Google Gemini 3.1 Pro Preview use every term in all 15 glossary languages where we shortlisted them, and translations from Microsoft Translator have a median of 13.9 terminology errors per 1,000 words.

Translations into Chinese Simplified and Ukrainian have the most, a median of 1.1 and 0.8 terminology errors per 1,000 words. Two-step and three-step solutions fix nearly every case, though the repair in three-step solutions can also paraphrase a term that was right. We evaluated these repairs on LLM solutions. MT engine solutions fell short on too many requirements to enter this repair comparison.

Terminology errors per 1,000 words, one-step solutions, median by model
Chart data
Terminology errors per 1,000 words, one-step solutions, median by model
ModelTerminology errors per 1,000 words, one-step solutions, medianType
Google Gemini 3.1 Pro Preview0LLMs
Anthropic Claude Fable 50LLMs
OpenAI GPT-4.10LLMs
Anthropic Claude Sonnet 4.60LLMs
Anthropic Claude Opus 4.80LLMs
Google Gemini 3.5 Flash0LLMs
DeepL Next Gen0.5LLM-based MT engines
Anthropic Claude Sonnet 50.8LLMs
Cohere Command A Translate1LLMs
Microsoft Translator13.9MT engines
Key takeaway 32 · Quality

Register errors occur in 52% of MT engine translations and 9% of LLM translations.

Among the evaluated LLM solutions with register errors, 68% meet the requirement after two steps and 73% after three. Tone of voice requires the formal register in every sentence in the second person or the imperative, such as Sie in German and 敬語 in Japanese.

Translations from LLM-based MT engines have register errors in 28% of the cases. Translations from Microsoft Translator have the most, a mean of 3.8 register errors per 1,000 words, and translations from Anthropic Claude Fable 5, Anthropic Claude Sonnet 5 and z.ai GLM-5 a mean below 0.05.

Translations into Cebuano, Finnish and Sundanese have the most, a mean of 7.8, 5.3 and 3.9 register errors per 1,000 words, and translations into 51 of the 82 languages have no register errors. We evaluated these repairs on LLM solutions. MT engine solutions fell short on too many requirements to enter this repair comparison.

Register errors per 1,000 words, one-step solutions, mean by model
Chart data
Register errors per 1,000 words, one-step solutions, mean by model
ModelRegister errors per 1,000 words, one-step solutions, meanType
Anthropic Claude Fable 50LLMs
Anthropic Claude Sonnet 50LLMs
z.ai GLM-50LLMs
OpenAI GPT-5.6 Sol0LLMs
Mistral Large 30LLMs
xAI Grok 4.20 (non-reasoning)0LLMs
Google Gemini 3.5 Flash0.1LLMs
OpenAI GPT-5.50.1LLMs
Anthropic Claude Opus 4.80.1LLMs
OpenAI GPT-4.10.1LLMs
Anthropic Claude Sonnet 4.60.1LLMs
OpenAI GPT-5.6 Luna0.1LLMs
OpenAI GPT-5.6 Terra0.1LLMs
DeepSeek V3.20.1LLMs
Google Gemini 3.1 Pro Preview0.2LLMs
Translated Lara 20.2LLM-based MT engines
xAI Grok 4.20 (reasoning)0.2LLMs
MoonshotAI Kimi K2.50.2LLMs
Google Gemma 40.4Open-weight LLMs
Cohere Command A Translate0.7LLMs
OpenAI gpt-oss-120b1.1Open-weight LLMs
Google Translation LLM1.3LLM-based MT engines
DeepL Next Gen1.4LLM-based MT engines
Widn AI Tower Sugarloaf1.9LLM-based MT engines
Microsoft Translator3.8MT engines
Key takeaway 33 · Quality

Tag errors occur in 98% of MT engine translations and 41% of LLM translations.

Where tags are the only problem, code repair restores them in 90% of the evaluated cases. Tag handling requires every HTML tag of the source, with its attributes, in the translation, since a broken tag can stop a translation from being imported or displayed correctly.

Translations from LLM-based MT engines lose tags in 80% of the cases. Translations from Google Gemini 3.1 Pro Preview keep every tag in 72 of the 75 languages where we shortlisted them, translations from Anthropic Claude Opus 4.8 in 11 of 45, and translations from DeepL Next Gen lose tags in every language where we shortlisted them.

Translations into European Spanish, Japanese, Chinese Simplified and Marathi have the most tag errors, a median of 2.0 to 2.3 per 1,000 words. Where general translation quality also falls short, two-step solutions (translation + post-edit) restore the tags in 59% of the cases and three-step solutions (translation + LQA + repair) in 56%. We evaluated these repairs on LLM solutions. MT engine solutions fell short on too many requirements to enter this repair comparison.

Tag errors per 1,000 words, one-step solutions, median by model
Chart data
Tag errors per 1,000 words, one-step solutions, median by model
ModelTag errors per 1,000 words, one-step solutions, medianType
Google Gemini 3.1 Pro Preview0LLMs
Google Gemini 3.5 Flash0LLMs
Anthropic Claude Fable 50LLMs
OpenAI GPT-5.50LLMs
Translated Lara 20LLM-based MT engines
OpenAI GPT-4.10LLMs
z.ai GLM-50LLMs
OpenAI GPT-5.6 Sol0LLMs
OpenAI GPT-5.6 Terra0LLMs
DeepSeek V3.20LLMs
OpenAI GPT-5.6 Luna0.7LLMs
xAI Grok 4.20 (reasoning)0.7LLMs
MoonshotAI Kimi K2.50.7LLMs
OpenAI gpt-oss-120b1Open-weight LLMs
Cohere Command A Translate1.2LLMs
Anthropic Claude Opus 4.81.3LLMs
Google Gemma 41.3Open-weight LLMs
Anthropic Claude Sonnet 51.3LLMs
Anthropic Claude Sonnet 4.61.3LLMs
Mistral Large 31.3LLMs
xAI Grok 4.20 (non-reasoning)1.3LLMs
Microsoft Translator5.9MT engines
Google Translation LLM8.2LLM-based MT engines
DeepL Next Gen9.2LLM-based MT engines
Widn AI Tower Sugarloaf59.8LLM-based MT engines
Key takeaway 34 · Quality

Unicode errors occur in 3% to 6% of LLM and MT engine translations, compared with 16% for open-weight LLMs.

Unicode character integrity requires every character of the translation intact, with no corrupted characters and no letter from another script that only looks like the right one.

Look-alike letters from another script occur most often in Kyrgyz, Tatar and Macedonian, and in Slovak, translations from Google Gemini 3.5 Flash, z.ai GLM-5, DeepL Next Gen and Google Translation LLM carry corrupted characters. Translations from Google Gemma 4 keep Unicode characters intact in 30 of 37 languages, and translations from 9 of the 25 models on eight or more shortlists in every language.

Three-step solutions (translation + LQA + repair) fix every Unicode error of the one-step solutions we built them on. We evaluated these repairs on LLM solutions. MT engine solutions fell short on too many requirements to enter this repair comparison.

Languages with and without Unicode errors, by model
Chart data
Languages with and without Unicode errors, by model
ModelLanguages with Unicode characters intactOther languages where we shortlisted the modelTotal
Google Gemini 3.1 Pro Preview75075
DeepL Next Gen66369
Google Gemini 3.5 Flash62163
Anthropic Claude Fable 560060
OpenAI GPT-5.557259
Anthropic Claude Opus 4.844145
OpenAI GPT-4.143043
Translated Lara 243144
Anthropic Claude Sonnet 533235
OpenAI GPT-5.6 Sol32032
Microsoft Translator31132
z.ai GLM-531233
Google Gemma 430737
Anthropic Claude Sonnet 4.629231
Mistral Large 327128
Google Translation LLM27532
OpenAI GPT-5.6 Luna26026
Cohere Command A Translate21122
OpenAI GPT-5.6 Terra18220
xAI Grok 4.20 (reasoning)15015
DeepSeek V3.214014
OpenAI gpt-oss-120b12214
MoonshotAI Kimi K2.511011
Widn AI Tower Sugarloaf10010
xAI Grok 4.20 (non-reasoning)628
Key takeaway 35 · Quality

The translated JSON document is invalid in 92% of MT engine cases and 3% of LLM cases.

All evaluated two-step and three-step repairs of invalid JSON produced valid documents. Valid JSON requires the translated JSON document to still parse, since an invalid JSON document can stop a translation from being imported.

Translations from LLM-based MT engines have an invalid JSON document in 74% of the cases, and translations from Translated Lara 2, Microsoft Translator, Google Translation LLM, Widn AI Tower Sugarloaf and Amazon Translate in every language where we shortlisted them. Among LLMs, translations from Anthropic Claude Sonnet 4.6 have one in 10 of 31 languages, and translations from open-weight LLMs always return a valid one.

In Marathi and Georgian, most of the invalid documents come from the LLM-based MT engines on the shortlist. We evaluated these repairs on LLM solutions. MT engine solutions fell short on too many requirements to enter this repair comparison.

Languages with valid and invalid translated JSON, by model
Chart data
Languages with valid and invalid translated JSON, by model
ModelLanguages with a valid JSON documentOther languages where we shortlisted the modelTotal
Google Gemini 3.1 Pro Preview75075
Google Gemini 3.5 Flash62163
OpenAI GPT-5.559059
Anthropic Claude Fable 559160
Anthropic Claude Opus 4.845045
OpenAI GPT-4.142143
DeepL Next Gen402969
Google Gemma 437037
Anthropic Claude Sonnet 535035
OpenAI GPT-5.6 Sol32032
z.ai GLM-532133
Mistral Large 327128
OpenAI GPT-5.6 Luna26026
Cohere Command A Translate21122
Anthropic Claude Sonnet 4.6211031
OpenAI GPT-5.6 Terra20020
xAI Grok 4.20 (reasoning)15015
OpenAI gpt-oss-120b14014
DeepSeek V3.213114
MoonshotAI Kimi K2.510111
xAI Grok 4.20 (non-reasoning)718
Widn AI Tower Sugarloaf01010
Google Translation LLM03232
Microsoft Translator03232
Translated Lara 204444
Key takeaway 36 · Quality

Gender-neutrality errors have a median rate of 3.1 per 1,000 words in gendered and natural-gender languages, compared with 0 in genderless languages.

Gender neutrality requires a gender-neutral translation wherever the English source leaves the gender of a person open, as in "your manager" or "the expert", which Spanish, German and Arabic would mark.

Two or more one-step solutions are fully gender-neutral in 40 of the 82 languages, 25 of them genderless languages, which have no gendered nouns or pronouns. In 42 languages, among them the Romance and Slavic languages, German, Greek, Arabic and Hebrew, translations from every shortlisted model have gender-neutrality errors. By type, translations from LLMs have them in 57% of the cases and translations from MT engines in 78%.

Where the two best solutions of a language are not fully gender-neutral, we add the gender-neutrality agent, which makes 47% of the one-step versions fully gender-neutral, 54% of the two-step versions (translation + post-edit) and 68% of the three-step versions (translation + LQA + repair).

Gender-neutrality errors per 1,000 words, one-step solutions, median by model
Chart data
Gender-neutrality errors per 1,000 words, one-step solutions, median by model
ModelGender-neutrality errors per 1,000 words, one-step solutions, medianType
Anthropic Claude Opus 4.80LLMs
Google Translation LLM0.2LLM-based MT engines
OpenAI GPT-5.6 Luna0.2LLMs
OpenAI GPT-5.50.3LLMs
z.ai GLM-50.3LLMs
DeepSeek V3.20.3LLMs
MoonshotAI Kimi K2.50.4LLMs
xAI Grok 4.20 (non-reasoning)0.4LLMs
Google Gemini 3.5 Flash0.7LLMs
OpenAI GPT-5.6 Terra1.2LLMs
Google Gemini 3.1 Pro Preview1.4LLMs
Google Gemma 41.4Open-weight LLMs
xAI Grok 4.20 (reasoning)1.4LLMs
OpenAI gpt-oss-120b1.4Open-weight LLMs
Anthropic Claude Fable 51.5LLMs
Translated Lara 21.7LLM-based MT engines
OpenAI GPT-5.6 Sol1.9LLMs
Anthropic Claude Sonnet 4.62.2LLMs
Mistral Large 32.2LLMs
DeepL Next Gen2.4LLM-based MT engines
Anthropic Claude Sonnet 52.4LLMs
OpenAI GPT-4.12.5LLMs
Microsoft Translator3MT engines
Cohere Command A Translate3.2LLMs
Widn AI Tower Sugarloaf3.3LLM-based MT engines
Key takeaway 37 · Costs

We calculate translation costs using August 2026 list prices and the measured tokens and characters.

Vendors sell translation per million tokens, per million characters, per word, per page, per request or by monthly subscription. We convert every price to US dollars per million characters of the English source, markup included, counting tokens with the tokenizer of each model. The four texts have 25,249 characters and 2,992 words, ~8.4 characters per word.

We take list prices from the vendor site, also for the models we used for free or on trial keys. For five models that are no longer on the price page, we use the last price the vendor listed, and for two open-weight models without a vendor API, the lowest price of an inference provider.

For 10 of the 55 models in our price check, there is no public price per token or per character. For seven of them, there is a quote or a sales contact instead of a price, a price shown only after sign-in, or no price list at all, and for three, the price is per word, per page or per request. Their solutions have no cost in our results.

For 11 models with reasoning, the cost leaves out the reasoning tokens, so it is a lower bound. For a two-step or three-step solution, we add up the cost of every step, the Intento LQA step included.

Key takeaway 38 · Costs

Within the same language, MT engine solutions cost ~5 times as much as LLM solutions at the median and have more errors.

At the median, a solution on an MT engine costs $24.99 per million characters and on an LLM $4.59, and MT engines cost more than LLMs in all 96 languages. Prices run from $0.11 on the open-weight Google Gemma 4, at the lowest price of an inference provider, to $100 on ALL-Lab, an MT engine.

Translations from MT engines have a median 58 errors per 1,000 words weighted by severity, against 31 from LLMs, and more errors in 79 of the 84 languages with an Intento LQA result for both. 0% of the MT engine solutions meet every Standard requirement, against 12% of the LLM solutions.

Within each type, the price follows the quality. In 43 of the 46 languages with three or more MT engine solutions, the more expensive MT engines have fewer errors, as DeepL Next Gen and Translated Lara 2 against Microsoft Translator, and in 79 of 82 languages, the more expensive LLMs.

Per word, the median solution costs ~$0.00006, while in the 2025 edition we priced human translation at $0.16 to $0.24 per word, ~2,700 to 4,100 times as much.

Cost and errors of the one-step solutions, by model
Chart data
Cost and errors of the one-step solutions, by model
ModelUS dollars per million characters, median over the languagesWeighted errors per 1,000 words, medianLanguagesClass
Google Gemma 4$0.1447.837Open-weight LLMs
OpenAI GPT-5.6 Luna$0.4528.926LLMs
Mistral Large 3$0.8245.328LLMs
Mistral Medium 3.1$1.0257.04LLMs
DeepSeek V3.2$1.2152.214LLMs
xAI Grok 4.20 (reasoning)$1.2343.516LLMs
MoonshotAI Kimi K2.5$1.2644.712LLMs
xAI Grok 4.20 (non-reasoning)$1.2867.69LLMs
z.ai GLM-5$2.4043.233LLMs
OpenAI GPT-4.1$3.0640.245LLMs
Google Gemini 3.5 Flash$3.5735.964LLMs
OpenAI GPT-5.6 Terra$4.5620.620LLMs
Google Gemini 3.1 Pro Preview$4.7625.276LLMs
Anthropic Claude Sonnet 5$5.9835.335LLMs
Anthropic Claude Sonnet 4.6$7.3735.631LLMs
OpenAI GPT-5.6 Sol$7.9018.833LLMs
Microsoft Translator$10.0067.932MT engines
Widn AI Tower Sugarloaf$10.0060.210LLM-based MT engines
OpenAI GPT-5.5$11.6122.862LLMs
Amazon$15.0076.17MT engines
Anthropic Claude Opus 4.8$15.8325.446LLMs
Google Cloud Advanced Translation API$20.00121.34MT engines
Google Translation LLM$21.3281.932LLM-based MT engines
Translated Lara 2$24.9938.244LLM-based MT engines
DeepL Next Gen$27.5042.871LLM-based MT engines
Anthropic Claude Fable 5$32.2819.460LLMs
Key takeaway 39 · Costs

A three-step solution costs a median of ~$590 per million source characters, mostly for Intento LQA.

The three-step median is ~30 times the two-step median and ~110 times the adjusted-LLM median. A one-step solution costs a median $27.50 per million characters on an off-the-shelf MT engine, LLM-based MT engines included, and $5.20 on an adjusted LLM. Tone of voice and a glossary in the request add ~2.5% to the cost of an LLM translation and nothing to an MT engine with a price per source character. A two-step solution (translation + post-edit) costs ~2.5 times as much as the one-step solution it starts from.

In a three-step solution (translation + LQA + repair), ~96% of the cost is the Intento LQA step, where we send every sentence to three LLM judges and their findings to a fourth LLM that combines them. A gender-neutral version costs a few percent more to translate than the solution it is a version of, and ~$1,000 as a three-step solution, gender checks included.

Each range covers several models and up to 96 languages. With billing on tokens, the same text costs more in languages with a longer translation and more tokens per character, so the ranges depend on the languages as well as on the models.

We use unified billing in Intento Language Hub to estimate costs across these model-and-harness workflows, including the Intento LQA step.

Cost of the solutions per million characters, by level of solution complexity
Chart data
Cost of the solutions per million characters, by level of solution complexity
Level of solution complexityLowest, US dollars per million charactersLower quartile, US dollars per million charactersMedian, US dollars per million charactersUpper quartile, US dollars per million charactersHighest, US dollars per million charactersNote
Off-the-shelf NMT$3.94$10.00$27.50$27.50$100.0094 languages
Adjusted NMT$18.66$21.16$21.70$27.50$27.5048 languages
Off-the-shelf LLM$1.05$1.84$3.34$4.26$10.005 languages
Adjusted LLM$0.11$2.78$5.23$12.49$50.7096 languages
Two-step solution$0.28$9.10$18.28$35.35$107.1264 languages
Three-step solution$489.93$567.07$593.44$629.73$767.9644 languages
Multi-agent system$0.40$17.76$56.78$994.12$1,194.3952 languages
Key takeaway 40 · Costs

Meeting Standard requirements costs a similar amount to Basic in 47 of 53 languages, while Advanced costs more in 18.

We compare the cheapest solution that meets the requirements of each quality level in the same languages, those where two solutions meet every Advanced requirement. In most of them, the cheapest solution that meets general translation quality (no critical error, at most three major errors and at most 20 weighted errors per 1,000 words) also meets the other Standard requirements, or meets them as a two-step solution (translation + repair by code) at no extra cost.

In Marathi and Thai, only three-step solutions (translation + LQA + repair) meet the Standard requirements, at ~$550 per million characters against $8.20 and $21.28 for the Basic requirements.

Meeting the Advanced requirements costs 10 times as much or more in four languages, such as Telugu ($29.87 to $929 per million characters). We check gender neutrality only on the two best solutions of each language, those with the fewest errors, so the cheapest solution that meets the Advanced requirements often runs on a more expensive model or takes more steps.

Where the gender-neutrality agent works with a three-step solution, its gender checks add ~$400 per million characters, as in Amharic ($612 to $1,043).

Languages by the cost change between sets of quality requirements
Chart data
Languages by the cost change between sets of quality requirements
Cost change between sets of quality requirementsAbout the same (within 10%)10% more to 2 times as much2 to 10 times as much, languages10 times as much or more, languages
Basic to Standard47213
Standard to Advanced35864
Key takeaway 41 · Performance

We compare translation time per 1,000 source words because the test texts differ in length.

The four source texts range from 270 to 999 words. We model translation time as a fixed time per request plus a time per word. With MT engines, most of it is the fixed time (~1.7 seconds per request for Yandex Cloud Translate v2), and with most LLMs it is the time per word (~0.06 seconds per word for Anthropic Claude Sonnet 5), so with an MT engine a short text takes more time per word.

We record the time of each text while we translate it, and for the models we call through the Intento platform, we take it from the platform logs, so these times are indicative.

Key takeaway 42 · Performance

No assessed real-time one-step solution meets every Standard requirement.

We assessed real-time one-step solutions in 84 languages, from MT engines such as DeepL Next Gen, Translated Lara 2 and Microsoft Translator and from OpenAI gpt-oss-120b. Only two meet general translation quality (no critical error, at most three major errors and at most 20 weighted errors per 1,000 words), DeepL Next Gen in German and Romanian. 4 out of 198 meet both tag handling and formatting. A repair of tags and formatting by code does not add time, but it leaves general translation quality as it is.

The one-step solutions that meet every Standard requirement come from LLMs adjusted with context in the request. The fastest is Google Gemini 3.5 Flash in Indonesian at ~12 seconds per 1,000 source words, and across the 38 languages where such a solution exists, the fastest one takes a median of ~65 seconds per 1,000 words. Within a language, the LLM solutions that meet every Standard requirement take ~1.1 times as long as the other LLM solutions at the median, and longer in 27 of the 38 languages.

One-step solutions by translation time and the Standard requirements they meet
Chart data
One-step solutions by translation time and the Standard requirements they meet (903 points by group)
StatusPointsLowest, seconds per 1,000 source words over the four textsLower quartile, seconds per 1,000 source words over the four textsMedian, seconds per 1,000 source words over the four textsUpper quartile, seconds per 1,000 source words over the four textsHighest, seconds per 1,000 source words over the four texts
Other solutions8260.136.2949.22596.2453,897.34
Meet every requirement7711.9454.0467.5285.18259.15

All 903 points →

Key takeaway 43 · Performance

Two-step solutions take ~twice as long as the same solutions in one step, and three-step solutions ~three times as long.

In each LLM step, we get the whole text again from the LLM, so a post-edit or a repair takes about as long as the translation. We estimate the LQA step at ~85 seconds per 1,000 words, with all its requests in parallel. Two-step solutions (translation + repair by code) take as long as the same solutions in one step, since the repair of tags and formatting by code does not add measurable time.

In the 42 languages where only two-step or three-step solutions meet every Standard requirement, the fastest of them takes a median of ~190 seconds per 1,000 words, against ~60 seconds per 1,000 words where a one-step solution does.

We implement these workflows in Intento Language Hub. Timings from platform logs cover the model calls made through the Hub. The Intento LQA duration here remains an estimate.

Median time per 1,000 words of two-step and three-step solutions, by step
Chart data
Median time per 1,000 words of two-step and three-step solutions, by step
StepTranslation, s per 1,000 wordsIntento LQA step (estimate), s per 1,000 wordsPost-edit or repair, s per 1,000 wordsTotal, s per 1,000 words
Two-step (translation + repair by code)96.80096.8
Two-step (translation + post-edit)81.8084.2177.3
Three-step (translation + LQA + repair)838686.15260.45
Key takeaway 44 · Performance

Meeting Standard requirements takes a similar time to Basic in 45 of 53 languages, while Advanced takes longer in 18.

We compare the fastest solution that meets the requirements of each quality level in the same languages, those where two solutions meet every Advanced requirement. In German, the fastest solution that meets the Basic requirements is real-time (DeepL Next Gen, under 1 second per 1,000 words), and the fastest one that meets the Standard requirements takes 30 seconds per 1,000 words, a two-step solution (translation + post-edit) on OpenAI GPT-5.6 Luna.

Meeting the Advanced requirements takes 2 to 4.4 times as long in eight languages, such as Bulgarian (26 to 116 seconds per 1,000 words). We check gender neutrality only on the two best solutions of each language, those with the fewest errors, so the fastest solution that meets the Advanced requirements often runs on a slower model or takes more steps.

Languages by the translation-time change between sets of quality requirements
Chart data
Languages by the translation-time change between sets of quality requirements
Translation-time change between sets of quality requirementsLess (by more than 10%)About the same (within 10%)10% more to 2 times as long2 to 10 times as long, languages10 times as long or more, languages
Basic to Standard045431
Standard to Advanced1341080

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