If needed, the tutorial below can help show you how to change your display language, and how to install a language pack (ex: English) if needed first.
Display Language - Change
The Language bar
would only be good to quickly change the keyboard layout or input language. As for a change display language shortcut, I suppose that you could use the "Keyboards and Languages" shortcut option in the tutorial below to help make it a bit easier to change the display language.
Region and Language Shortcut - Create
Hope this helps,