I believe anyone can learn klingon quite fast, as long as there are three things:

1. he *really* wants it
2. he's willing to work systematically 
3. there are people who are willing to help him

I wouldn't have learned a thing, if everyone here wouldn't have done everything to help me, something for which I'm truly grateful.

There's no way someone could learn alone, not in a million years.

Anyways..

In my opinion, the most difficult thing in klingon isn't learning the grammar, the vocabulary, the prefixes, or suffixes..

The most difficult thing, is freeing your mind from the habits of your native language, and stop trying to translate word-for-word, natural languages in klingon.

~ mayqel qunen'oS