My iPad is in English but apps are in Russian. Why?
I just had the same problem and I solved it. My iPhone apps were very often in German but my iPhone was in Swedish. The problem is: I believe that your iPad's secondary language is set to Russian (Apps display in the first language they find on your list for which they have a localization included). So I believe that if you change your secondary language you should have apps in your desired language. To change secondary language, go to Settings > General > International > Language and choose whatever language you want (presumably English in your case) as secondary language. Then, when the language is set, switch back to your original language and you shall be all set.