The only and fastest way I know is to create a shortcut to the languages menu in settings.
1. Get Activity Launcher from Google Play
2. In Activity Launcher, search for "Languages"
3. Go to the "Settings" section. There should be an activity called "Languages" which links to com.android.settings.Settings$LocalePickerActivity
4. Create a shortcut to your homescreen to this activity by longpressing on it.
I hope this helps