As for languages...
I think English is pretty easy when it comes to studying it from the very beginning. To start speak bad English is much easier than to start to speak bad Russian. I mean it makes no dificullty to explain "I go, you go, he goes" or "I have, you have, he has" etc. But when you try to explain "Я иду, ты идёшь, он идёт" or "вижу, видишь" or "У меня есть", you inevitably stumbles over all those endings, root alternations and impersonal constructions, so if the student is not familiar with language terms, it almost impossible to say "WHY", it shoud be only remembered then.
On the other hand, to get the real fluency in English is almost as hard as to get fluency in any other language.