Localisation

The lang package translates text and formats values for the user’s locale: their language and region, such as en-US or de-DE.

Bellui’s own text, such as “Cancel” in dialogs, the month names in the date picker and the items of the text edit menu, is already translated into 15 languages: Chinese (Simplified), Czech, English, French, German, Greek, Japanese, Polish, Portuguese, Portuguese (Brazil), Russian, Spanish, Swedish, Tamil and Ukrainian. You add translations for your app’s own text.

How the locale is chosen

At startup Bellui reads the user’s preferred locales from the operating system.

• Translations use the closest language that has translations, among Bellui’s own and the ones you add. When none matches, English is used.
• Formats, sorting and text direction use the full locale, including the region. Users with en-US and en-GB get the same English text, but dates as 03/09/2026 and 09/03/2026, and prices in dollars and pounds.

lang.SystemLocale returns the operating system’s locale. lang.CurrentLocale returns the locale in use, which differs when the app has chosen one with lang.SetLocale.

On Android, Bellui reads the locale again when the app starts, when it comes back to the foreground, and when the user changes the app’s language in the system settings, so a language change made while the app was in the background is picked up.

Right-to-left languages

A locale written in a right-to-left script, such as Arabic, Hebrew, Persian or Urdu, also mirrors the layout. This happens automatically: the app does not need to call anything. Bellui has no translation of its own text into these languages, and no bundled text font with their letters, so check Right-to-left languages before you ship one. It also lists what does not mirror and the limits of mixed-direction text in v1.0.0.