Jev knowledge base·verified Sep 22, 2026

jev language support

TypeSafe says Jev is strongest in English. Build per-language labels, questions, calibration, code-switch tests and monitored rollout.

the short answer

TypeSafe’s model documentation says Jev is strongest in English. It does not provide a complete per-language quality table that supports treating all languages as equivalent. Jev can receive text in other languages, but production support must be established per language, locale and criterion with native-speaker labels, calibration, boundary tests and monitored coverage. Translate or route unsupported cases explicitly rather than assuming parity.

Official guidance
English is strongest
Complete language matrix
Not published in the reviewed model docs
Unit of validation
Language × locale × criterion × domain
Code switching
Test as a separate slice
Safe rollout
Offline labels, shadow traffic, bounded coverage

“Accepts Text” Is Not the Same as Validated Support

A request may complete in a language even when its error rate or probability calibration is unsuitable for the application. Language support includes vocabulary, grammar, dialect, locale conventions, domain terminology and the criterion wording—not merely successful tokenization.

The only broad official statement used here is that English is strongest. Do not turn anecdotal success in one language into a product-wide support claim. Date every tested model and provider.

Define Support as a Deployment Matrix

Publish a support claim only for cells with enough representative evidence. “Spanish customer-support routing on jev-1.13.0” is testable; “multilingual Jev” is too broad.

DimensionWhy it changes the result
Language and scriptLexical and writing-system coverage differ
LocaleDates, numbers, currency and policy meaning differ
DomainLegal, medical and product vocabulary differ
CriterionRouting may work where nuanced safety judgment does not
State/question languageTranslated instructions can change semantics
Code switchingEvidence may mix languages within one case

Choose a Language Strategy and Test Its Failure Modes

Never hide machine translation inside preprocessing without versioning it. The translator becomes part of the evaluator and must be included in error analysis.

StrategyBenefitRisk
Question and state in source languageAvoid translation lossQuestion behavior may vary by language
Question in English, state in source languageOne maintained rubricCross-language interpretation may weaken
Translate state to English firstUses strongest stated languageTranslation can alter evidence or protected terms
Route unsupported languages to reviewLimits automation riskAdds cost and delay

Treat Translation as a Separate Measured Component

A disagreement can originate in translation or in Jev. Retain both versions so reviewers can attribute it. Test named entities, negation, politeness, idioms, dates and domain terminology with meaning-preserving and meaning-changing pairs. If translation adds more latency, cost or error than direct evaluation, route that language directly or keep it in human review.

01Original evidencePreserve the source-language text and locale metadata.
02TranslationRecord provider, model, prompt, output and detected omissions.
03Jev questionEvaluate the translated state with a versioned English criterion.
04DecisionApply language-specific thresholds or route to review.
05AuditA native reviewer checks the original text, not only the translation.
A translated Jev path contains two models and two places meaning can change.

Use Native Labels and Locale-Specific Boundary Cases

  • Recruit reviewers fluent in the language and familiar with the domain.
  • Preserve original text; store translations as separate versioned fields.
  • Include dialect, slang, politeness, negation, transliteration and code switching.
  • Test dates, decimal separators, currencies and named entities explicitly.
  • Measure reviewer agreement before attributing disagreement to Jev.
  • Keep each language represented in untouched release and monitoring sets.

Report Performance and Calibration per Language

An aggregate score weighted toward English can conceal severe errors in smaller languages. Report class-specific errors, Brier or log loss, action coverage, unscorable rate and review load per supported cell. Include uncertainty because small samples can make apparent rankings unstable.

Do not copy English thresholds into another language. Fit on separate calibration evidence, then evaluate once on held-out examples. The dataset guide covers grouping and leakage; monitoring covers production slices.

Store Language and Translation Lineage with Every Result

This application record makes the path reproducible; it is not a TypeSafe response schema. Keep locale separate from detected language because regional vocabulary and numeric conventions can change meaning. A code-switched message may need multiple language tags or its own slice rather than one forced label.

{
  "source_language": "es-MX",
  "language_method": "translated_to_en",
  "translation_version": "translator-x.prompt-v3",
  "original_evidence_ref": "message://m-418",
  "translated_evidence_ref": "projection://m-418-en-v3",
  "jev_model": "jev-1.13.0",
  "question_version": "refund_request.en.v2",
  "raw_answer": { "noul": 0.76 },
  "threshold_version": "refund_request.es-MX.v1"
}

Roll Out One Validated Language Slice at a Time

01InventoryMeasure language, locale and code-switch traffic.
02LabelBuild native-reviewed datasets for one criterion.
03CompareTest direct, translated and human-review paths.
04ShadowObserve live distributions and missing evidence.
05LaunchAutomate only validated bands with fallback.
06MonitorAudit every language and version over time.
Language support is earned through evidence, not enabled by a locale flag.

Define Support Levels from Measured Behavior

Support attaches to a language, locale, criterion, domain, projection and model version—not to the language name alone. Publish sample size, label process, error bounds and known exclusions beside the status. Reopen the gate after a model, translator, rubric or traffic change. The evaluator scorecard provides the release dimensions.

StatusMeaningAllowed use
UnsupportedNo representative validation setDo not automate; collect evidence or route elsewhere
ExperimentalOffline evidence exists but live behavior is unmeasuredShadow or reviewer-assist only
LimitedSpecific criterion and slice meet release targetsAutomate only the validated bands with audit sampling
SupportedSustained quality, calibration, coverage and operations meet documented targetsProduction use within the tested scope

FAQ

Is Jev English-only?

TypeSafe says Jev is strongest in English, not that other text is categorically rejected. Validate every non-English deployment independently.

Should I translate all state into English?

Not automatically. Compare direct and translated paths because translation can remove or change evidence and adds another model dependency.

Can one threshold work across languages?

Do not assume so. Check calibration and error costs separately, then choose language-specific operating points if supported by evidence.

How should code-switched text be tested?

Treat it as its own production slice with representative native review, rather than assigning it to whichever language appears most often.

Sources

Checked against the sources below on September 22, 2026. Model versions, prices and limits change.

  1. TypeSafe AI docs: Models
  2. TypeSafe AI docs: State
  3. TypeSafe AI docs: Jev 1.13 jaggedness
  4. TypeSafe AI docs: Primitives
  5. NIST AI RMF: Measure function