Type change language settings into search bit on FB.
Click on the top page which comes up in whatever language.
There should be a white box - drop-down - to hopefully find English, click and cross fingers.
Try the method in the video that Mamya & I posted. (NB: It's a lot easier to see what's going on if you click on the 'Full screen' icon at the bottom right of the video. Press 'Esc' to exit full screen).
If you encounter a problem, please tell us how far you get.
(Note: I wouldn't recommend trying that method on a mobile device. It's likely to be far easier from a PC)
I seemed to be doing this a couple of times a week and wondered why. Yesterday I Realised why. I Use the web page for Facebook and not the app on my ipad IF you are using the same then the answer is.. look at the bottom of the page on the right hand side under where the adverts are, yep that's where you can choose to change language,It is so easy to just touch this to get a different language. Hope this helps.