Languages

Languages are configured in the Studio, not in code: Site Settings → Languages holds the site language, the other languages and the fallback setting. Editors can turn them on without a deploy. See Translating content for the editor side.

In the Studio

Pages, collections and entries are translated with @sanity/document-internationalization: one document per language, each with a language field, linked by a translation.metadata document.

• supportedLanguages is read from Site Settings when the Studio loads (getLanguages() in schemaTypes/shared/language.ts), so reload after changing languages.
• New documents start in the site language through the language field's initial value.
• Slugs only need to be unique within a language (isUniqueInLanguage).
• When an entry is translated, the plugin's callback in sanity.config.ts points the copy at the collection's translation in the same language.
• Site Settings per language are documents with the IDs settings-<language>, listed by structure.ts.

Documents created before languages were turned on have no language. Queries treat them as the site language with coalesce(language, $defaultLanguage).

URLs

The site language has no prefix; every other language has its tag as the first segment.

splitLanguagePath() in app/utils/language.ts reads the language from a path, and localePath() adds it. A prefix for the site language (/en/about) redirects to the unprefixed URL; the Presentation tool links that way, since it does not know the site language.

Queries

• IN_LANGUAGE selects documents in the current language.
• translated('page') follows a reference to its translation in the current language, falling back to the referenced document. Links and Collection List blocks use it, so they can point at one language and still follow the visitor.
• TRANSLATIONS lists the language versions of a document; the language switcher and the hreflang links use it.
• find() looks up a document in the current language, then, with $fallback, in the site language. The result's language tells the page it is showing a fallback, which then adds a note and noindex.

Site Settings and interface text

SETTINGS_QUERY reads each translatable field from settings-<language> first and falls back to the main settings. Interface text (labels) is merged in app.vue: English defaults from app/utils/labels.ts, then the main settings, then the current language. Components read it with useLabels():

const t = useLabels()t('photos', { count: 12 }) // "12 photos", or the translated label

To add a label, add it to DEFAULT_LABELS in labels.ts and to LABELS in the settings schema.

Nuxt UI text

Nuxt UI translates its own text (close buttons, carousel arrows, the search placeholder) through locales. modules/ui-locales.ts generates one lazy import per Nuxt UI locale, and loadUiLocale() loads only the language being viewed, picking the closest match: pt-BR → pt_br, then pt, then English. app.vue passes it to <UApp :locale>.

SEO

• <html lang> and og:locale follow the page language. Nuxt SEO sets them from its site config, which knows one language only, so app.vue rewrites the final tags in a tags:resolve hook.
• Pages with translations get hreflang links, with x-default on the site language.
• The sitemap lists every language and adds the translations of each URL as alternatives.