help with changing language on facebook

When using my Linx 10 tablet to get onto facebook, I must have inadvertently changed the language, it looks like a form of Arabic, so as apart from names and anything I have posted which is still in English, I can't see where I can alter the language as obviously all other instructions and commands are in the foreign language. I use facebook to keep in touch with my grandchildren so any help would be greatly appreciated.
Thanks,
Ken

help with changing language on facebook