You must be in device shell to run this command or else use command like this adb shell 'setprop persist.sys.language fr;setprop persist.sys.country CA;stop;sleep 5;start' as explained in that here (http://developer.android.com/guide/topics/resources/localization.html#testing) you can change it only emulator not on device. I suppose changing language on android device has to be done manually