pronunciation
I have to say I was a bit surprised at the last poll results. Out of some 150+ votes a whopping 62% responded saying pronunciation was the most difficult part of learning Chinese. I purposely left the writing system out of the equation because I was most interested in what makes speaking difficult. I was guessing it would have been the confidence issue, and that did come in a distant second.
If you are one who feels pronunciation is impeding your Chinese abilities, I guess you are in the right place (perhaps my results are skewed — in a way this is a pronunciation activity site). But confidence is key to improving pronunciation. If you speak in full voice, practice shouting even, your tutors, instructors and even yourself will be more likely to correct your errors. Mumbling is a sure way to have mistakes reinforced. And it is difficult to fix a mistake you have made for years.
Practice loud! Practice Proud!

I've been teaching Chinese since 1998. This site was built to help my students practice the sounds of Chinese. Hope it continues to help others. Let me know if you have questions.