Safari on iOS prior to 10.2, the country code returned is lowercase: "en-us", "fr-fr" Navigator.language - Web APIs | MDNThe Navigator.language read-only property returns a string representing the preferred language of the user, usually the language of the browser UI. A . stores a string representing the language version as defined in BCP 47. Examples of valid language codes include "en", "en-US", "fr", "fr-FR", "es-ES", etc.https://developer.mozilla.org/en-US/docs/Web/API/Navigator/language