Actually vocabulary is more important and difficult. Here in America, we do not really value one's English depending on one's pronunciation. In fact, we do care about the idea people try to express instead of the way they pronounce. My professor in neurobiology is an Indian who immigrated to the states when he was 17. Of course he still carries a strong Indian accent with his English, but still, he is one of the most prestigious professors in neurobiology field regardless of his pronunciation.

Well, Kathleen, dear friend of mine, I think vocabulary is probably harder to learn for most people... however, sometimes pronunciation is very difficult to learn (and to teach) also. For instance, people who struggle with the "r" sound typically have a very hard time conquering that problem... Dylan, my brother, couldn't pronounce his "r's" till he was 11. As a side note, I guess as a teacher, it all boils down to personal opinion. For instance, I would be very impressed with a student whose vocabulary included the word, "rendezvous"... I would be even more impressed if he actually pronounced it correctly. :)

I think it's pronunciation. Using memory it's typical task for a human but using your voice for sounds you've never used before it's untypical and most difficult task.

all the sexual positions and the conversation in the bed

vocabulary