Internationalization, localization, and input methods in Fuchsia

This is the entry page to the internationalization (I18N), localization (L10N) and input methods (IM) subsystems in Fuchsia.


Modern user-facing operating systems need to support users across a variety of regions, languages, and cultures. Localization and internationalization are critical to this goal.

Localization (L10N) is the process of translating user interfaces into local languages and conventions. This includes text and image content, fonts, regional variations for components like date, time, text and imagery direction, currency, and number formats.

Internationalization (I18N) is the process of designing locale-independent software that makes localization in a wide range of languages, regions, and cultures easy.

Typically, localization refers to the work done by language experts, designers, tech writers, and other content producers. Internationalization refers to the work done by software engineers.

Fuchsia's approach

Because Fuchsia is designed to be extensible and to flexibly support a variety of runtimes and target products, the core operating system does not strictly specify how to implement i18n and l10n.

However, Fuchsia does include some basic conventions, shared libraries, and services for i18n/l10n, and uses these in the components and runners that are typically distributed with Fuchsia.

The following topics discuss the development of Fuchsia applications and the operating system itself, in multi-language environments.

  • Internationalization preferences: Fuchsia has guidelines for how to encode, read, and write i18n settings.

  • ICU library: In-tree components that need common i18n functionality such as formatting and parsing dates, times, and numbers, working with time zones, displaying bidirectional text, or selecting locales and languages can use the third-party ICU library.

    Out-of-tree components can also use ICU, but they need to bring their own copy of ICU because the library is not part of the official Fuchsia SDK.

  • ICU time zone data: Both in-tree and out-of-tree components that use ICU to deal with dates and times should consider using Fuchsia's shared ICU time zone data to ensure consistent time among components.

  • Localizing components: Fuchsia offers some basic guidance a string lookup library and workflow for C++ components.

  • Fonts: Fuchsia provides a FIDL service for loading font assets, with an API that is particularly useful for freetype2 clients.