Well... most of the english i speak today i learned reading LotR... my cousin gave me a version of it in english, and i had to struggle to understand it... at the first chapters, i would read with the dictionary on my lap, searching lots and lots of words... at the end, i was reading far better...
Anyway i did read the LotR, several times, the Hobbit, started the Silmarillion but never finished it, as my interests went to another things.