Languages

The site ships in eight languages. English is the default and the source every other language is checked against.

The list lives in i18n/routing.ts (LOCALES). English has no prefix in the URL; every other language has its code. The sitemap and the hreflang tags on each page list every language automatically.

Visitors pick a language with the switcher in the header. If you set NEXT_PUBLIC_LOCALE_DETECTION=true, first-time visitors are also sent to the language their browser asks for.

Where the text lives

Missing text falls back to English, key by key

i18n/request.ts loads the English file first and lays the translation over it. Any key the translation lacks, or leaves empty, shows the English text. A whole missing file shows English for that page. A list (for example the features on the landing page) is taken from the translation only when it has as many items as the English one; otherwise the English list shows.

So a half-translated language never breaks a page; it shows some English. The same holds for plan text: a plan without copy.<code> shows its English text.

Asking the agent to translate

The agent writes every language itself. Useful requests:

I changed the hero text in i18n/messages/en/Landing.json.
Update the same keys in the other seven languages, each written in its own language.

Check every language folder against English and translate any key that is missing or still in English.

Translate the card text of the new "pro-monthly" plan in config/pricing.ts into every language in LOCALES.

Name the source of truth (usually the English file) and ask for "written in its own language", not word-for-word translation. Have a native speaker read the pages that sell (landing, pricing) before launch.

For blog and glossary posts there is also a translate button in the admin editor; see Blog and glossary.

Adding a language

Tell the agent: "Add Portuguese (pt) as a ninth language." It works through this list:

1. i18n/routing.ts: add the code to LOCALES and one entry to each table below it: LOCALE_NAMES (the language's own name, shown in the switcher), SHORT_LOCALE_NAMES, LOCALE_ENGLISH_NAMES (used when telling an AI model which language to write), LOCALE_TO_HREFLANG (for example pt-BR).
2. proxy.ts: the locale list in the matcher (the line '/(en|zh|ja)/:path*'); the file's header asks to keep it in step with LOCALES.
3. i18n/messages/pt/: a copy of the en/ folder, translated. Anything left out shows English.
4. config/pricing.ts: a pt entry in each plan's copy.
5. content/about/pt.mdx: the About page.
6. public/og_pt.png: the social preview image for that language. The starter ships og.png, og_zh.png and og_ja.png only, so the other languages point to an image that does not exist until you add it.
7. Optional: blogs/pt/ for file-based posts.

Then it runs pnpm lint and opens a few pages under /pt/.

To remove a language, do the same in reverse. Pages already indexed by search engines in that language will answer 404.

When it fails