I agree, Mar. I know there are many ways to pronounce a letter, specially in Chinese. Anyway, there are some basic rules that we could try to expose, so if not perfectly, unless we could pronounce the nearest way to the right form. In my last book (Mike C, Lumia and Magia have each one) I've included a guide of pronunciation of several languages, included Chinese, but... only for spanishspeakers. Thanks.