Go to settings>language & input>voice input>tap on the gear icon next to " enhanced Google services ">tap on languages at tap,select your language from here (if listed) and check in the box.below tap on save button then return to settings>language & input>tap on language button in top,scroll down to the same language that you selected before tap on it Now all settings including home screen language, interface in language, Google keyboard board language will change as your selection.