Yeah unless you disable it, all browsers should be sending a language header to a site say I want content in X language. The developer still has to handle that,

Yeah unless you disable it, all browsers should be sending a language header to a site say I want content in X language. The developer still has to handle that, but it’s generally the safest way to guess what language a user is looking for. But you still should price a way to change it in the interface.