It's difficulty difficult to learn English.

Difficulty is a noun. We should use the adjective difficult instead.

My English is very poor even though if I spend a lot of time to learning it.

I often make the decistion to learn the English after I meet my foreign collaborators, but always be interrupt by some reasons.

I have made the decision to learn English many times after meeting foreign collaborators, but I always get distracted.

After some times such a long time, I always think about wonder whether if I can will be able to learn English well.

I am living in China, but I must communicate with my English speaking friends.

I think this is what you mean. If you just say friends, it could mean your Chinese friends, and the sentence would not make sense.

So I come here to learn. If you have time, please give me some help.

Thanks.