Currently X-UI supports I18N through polyglot. You can change the language by setting the locale, however routes should be able to offer the option for the following:

• router.go(ROUTE, { locale: "en" });

if route is "/path", it should also work with "/{locale}/path". The locale should automatically infered from URL. This might need a way to configure all available locales, and also allow locale by domain how NextJS does it.