I would like to respect the user’s language preferences for formatting (for example, mm/dd/yyyy vs dd.mm.yyyy) even if I don’t support their language and fall back to en.

Without i18next I can do this by passing the detected language, eg de-DE to the first parameter of the Intl.* APIs. I know I can do this on a one-by-one basis in i18next too, but is there a way to specify a default when initializing i18next?