We are working hard to fully support internationalization and translation in Arc, but for the moment the Arc app is only available in English.

That said, you can still change the primary language in your Arc settings to make sure websites are shown in your preferred language.

To do this, you'll remove all other languages from the browser except your language of choice, so all sites visited in this language won't be translated and any site not in this language will have the option to translate.

To do this head to arc://settings/languages and follow the steps shown in this video.