Glossary terminology in LLM and MT engine translations

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

How do LLMs and MT engines compare on glossary terminology?

In the 16 languages with a glossary, translations from LLMs have terminology errors in 43% of the cases, from LLM-based MT engines in 68%, from open-weight LLMs in 80% and from other MT engines in nearly every case. At the median, translations from LLMs have 0 terminology errors per 1,000 words, against ~0.5 for open-weight LLMs and LLM-based MT engines and 12.6 for other MT engines. Translations from Google Gemini 3.1 Pro Preview use every term in all 15 glossary languages where we shortlisted them.

Translations into eight of the 16 glossary languages have a median of 0 terminology errors per 1,000 words

These are Arabic, Belarusian, Dutch, German, Italian, Japanese, Korean and European Spanish. Translations into Chinese Simplified have the highest median, 1.1 terminology errors per 1,000 words, and into Ukrainian 0.8.

Terminology errors per 1,000 words by language, range of the one-step solutionsLowest to highestMiddle 50% of the shortlisted one-step solutionsMedian0510152025Arabic (MSA): lowest 0, middle half 0 to 0.6, median 0, highest 9.6Arabic (MSA)Belarusian: lowest 0, middle half 0 to 5.5, median 0, highest 21.6BelarusianDutch: lowest 0, middle half 0 to 1, median 0, highest 19.9DutchGerman: lowest 0, middle half 0 to 0.5, median 0, highest 14.7GermanItalian: lowest 0, middle half 0 to 0.5, median 0, highest 11.1ItalianJapanese: lowest 0, middle half 0 to 0.6, median 0, highest 16JapaneseKorean: lowest 0, middle half 0 to 1, median 0, highest 22.4KoreanSpanish (European): lowest 0, middle half 0 to 4.5, median 0, highest 10.2Spanish (European)French: lowest 0, middle half 0 to 1, median 0.2, highest 17.3FrenchRomanian: lowest 0, middle half 0 to 0.9, median 0.2, highest 17.9RomanianRussian: lowest 0, middle half 0 to 0.5, median 0.2, highest 10.1RussianPortuguese (European): lowest 0, middle half 0 to 0.5, median 0.4, highest 12Portuguese (European)Estonian: lowest 0, middle half 0 to 1.8, median 0.5, highest 19.6EstonianSerbian: lowest 0, middle half 0.2 to 0.8, median 0.5, highest 0.9SerbianUkrainian: lowest 0, middle half 0.2 to 0.9, median 0.8, highest 13.1UkrainianChinese Simplified: lowest 0, middle half 0.7 to 3.5, median 1.1, highest 15.2Chinese SimplifiedShortlisted one-step solutions in each of the 16 languages with a glossary, 121 glossary terms in the four texts. The box spans themiddle 50% of the solutions, from the lower to the upper quartile.

Translations from Microsoft Translator have a median of 13.9 terminology errors per 1,000 words, and translations from most LLMs 0

Translations from Google Gemini 3.1 Pro Preview, Anthropic Claude Fable 5, OpenAI GPT-4.1, Anthropic Claude Sonnet 4.6, Anthropic Claude Opus 4.8 and Google Gemini 3.5 Flash have a median of 0. Translations from DeepL Next Gen have 0.5, from Anthropic Claude Sonnet 5 0.8 and from Cohere Command A Translate 1.0.

Every one-step solution with terminology errors meets the requirement as a two-step or three-step solution

On the same solutions, the one-step solutions with terminology errors have no terminology errors as two-step solutions (translation + post-edit) and as three-step solutions (translation + LQA + repair). The repair in three-step solutions can also change a term that was right, most often by paraphrasing it. We measured these fixes on LLM solutions, since we leave out the MT engine solutions as too far off.

Disclaimers

  • Terminology applies in the 16 languages with a glossary. We score terminology with an LLM check that accepts declined forms, since in many languages a glossary term changes form inside a sentence.
  • We assess only the shortlisted one-step solutions (10 to 13 per language by COMET-Kiwi or MetricX, with at least three real-time solutions among them), so a model has no result in a language where it is not on the shortlist.
  • The results come from four business texts of ~3,000 words. Other content can show other results.
  • We build two-step and three-step solutions only in the languages with fewer than two solutions that meet every Standard requirement, so their results describe those languages.

Terminology of one-step solutions, by model

ModelTypeLanguages where we shortlisted itLanguages with no terminology errorsTerminology errors per 1,000 words, median
Google Gemini 3.1 Pro PreviewLLM15150
Anthropic Claude Fable 5LLM1270
OpenAI GPT-4.1LLM1060
Anthropic Claude Sonnet 4.6LLM960
Anthropic Claude Opus 4.8LLM850
Google Gemini 3.5 FlashLLM860
DeepL Next GenLLM-based MT engine1540.5
Anthropic Claude Sonnet 5LLM1020.8
Cohere Command A TranslateLLM1301
Microsoft TranslatorMT engine8013.9
OpenAI GPT-5.6 SolLLM750
Widn AI Tower SugarloafLLM-based MT engine740
OpenAI GPT-5.5LLM650
OpenAI GPT-5.6 LunaLLM430
z.ai GLM-5LLM430
xAI Grok 4.20 (reasoning)LLM330
AI21 Jamba Large 1.7LLM110
MoonshotAI Kimi K2.5LLM110
Google Gemma 4Open-weight LLM630.1
Mistral Medium 3.1LLM210.3
Meta Llama 4 MaverickOpen-weight LLM200.4
Translated Lara 2LLM-based MT engine620.5
DeepSeek V3.2LLM100.5
ModernMT Enterprise EditionMT engine100.5
Alibaba Qwen3-235B-A22BOpen-weight LLM200.6
Mistral Large 3LLM720.8
Anthropic Claude Haiku 4.5LLM100.9
OpenAI GPT-5.6 TerraLLM411
OpenAI gpt-oss-120bOpen-weight LLM402.4
Swiss AI Apertus-8B-2509Open-weight LLM108.1
ALL-LabMT engine109.6
Google Translation LLMLLM-based MT engine3010.1
Elia Machine Translation SystemMT engine1010.2
Yandex Cloud Translate v2MT engine2015.8
Amazon TranslateMT engine7016

One-step solutions with an Intento LQA result in 82 languages, the models on fewer than eight shortlists after the others. Terminology applies in the 16 languages with a glossary, 121 glossary terms in the four texts.

Terminology of one-step solutions, by language

LanguageTerminology errors per 1,000 words, medianModels with no terminology errors
Arabic (MSA)0
  • Anthropic Claude Fable 5
  • DeepL Next Gen
  • Google Gemini 3.1 Pro Preview
  • Google Gemini 3.5 Flash
  • Google Gemma 4
  • OpenAI GPT-4.1
  • OpenAI GPT-5.5
Belarusian0
  • Anthropic Claude Fable 5
  • Anthropic Claude Sonnet 4.6
  • Google Gemini 3.1 Pro Preview
  • Google Gemini 3.5 Flash
  • OpenAI GPT-5.6 Sol
  • z.ai GLM-5
Dutch0
  • Google Gemini 3.1 Pro Preview
  • Mistral Large 3
  • MoonshotAI Kimi K2.5
  • OpenAI GPT-4.1
  • OpenAI GPT-5.5
  • OpenAI GPT-5.6 Sol
  • xAI Grok 4.20 (reasoning)
  • z.ai GLM-5
German0
  • Anthropic Claude Opus 4.8
  • Anthropic Claude Sonnet 5
  • DeepL Next Gen
  • Google Gemini 3.1 Pro Preview
  • OpenAI GPT-4.1
  • OpenAI GPT-5.6 Luna
Italian0
  • Anthropic Claude Opus 4.8
  • Anthropic Claude Sonnet 4.6
  • DeepL Next Gen
  • Google Gemini 3.1 Pro Preview
  • Google Gemma 4
  • OpenAI GPT-5.5
  • OpenAI GPT-5.6 Luna
  • Widn AI Tower Sugarloaf
Japanese0
  • Anthropic Claude Fable 5
  • Anthropic Claude Opus 4.8
  • Google Gemini 3.1 Pro Preview
  • Google Gemini 3.5 Flash
  • Mistral Medium 3.1
  • Widn AI Tower Sugarloaf
Korean0
  • Anthropic Claude Fable 5
  • Anthropic Claude Sonnet 4.6
  • Anthropic Claude Sonnet 5
  • Google Gemini 3.1 Pro Preview
  • Google Gemini 3.5 Flash
  • Google Gemma 4
  • Translated Lara 2
Spanish (European)0
  • AI21 Jamba Large 1.7
  • DeepL Next Gen
  • Google Gemini 3.1 Pro Preview
  • OpenAI GPT-5.6 Terra
  • Widn AI Tower Sugarloaf
  • xAI Grok 4.20 (reasoning)
French0.2
  • Anthropic Claude Fable 5
  • Google Gemini 3.1 Pro Preview
  • Google Gemini 3.5 Flash
  • Mistral Large 3
  • OpenAI GPT-4.1
  • OpenAI GPT-5.5
Romanian0.2
  • Anthropic Claude Fable 5
  • Anthropic Claude Sonnet 4.6
  • Google Gemini 3.1 Pro Preview
  • OpenAI GPT-4.1
  • OpenAI GPT-5.6 Sol
  • z.ai GLM-5
Russian0.2
  • Google Gemini 3.1 Pro Preview
  • Google Gemini 3.5 Flash
  • OpenAI GPT-5.5
  • OpenAI GPT-5.6 Sol
Portuguese (European)0.4
  • Anthropic Claude Sonnet 4.6
  • OpenAI GPT-4.1
  • OpenAI GPT-5.6 Luna
  • Widn AI Tower Sugarloaf
Estonian0.5
  • Anthropic Claude Opus 4.8
  • Anthropic Claude Sonnet 4.6
  • Google Gemini 3.1 Pro Preview
  • OpenAI GPT-5.6 Sol
  • xAI Grok 4.20 (reasoning)
Serbian0.5
  • Anthropic Claude Fable 5
  • Google Gemini 3.1 Pro Preview
Ukrainian0.8
  • Google Gemini 3.1 Pro Preview
  • Translated Lara 2
Chinese Simplified1.1
  • Anthropic Claude Opus 4.8
  • Google Gemini 3.1 Pro Preview

One-step solutions with an Intento LQA result, in the languages where the requirement applies.

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