shouldn't be an issue for learners with English speaking background as they pronounce the same in both languages. The real challenge is with 'x' and 'z' unfortunately , both 'x' and z' are common initials in peoples names -- first name and last name -- I've friends who have their name begin with 'x' or 'z' and they are called all different from different people. an example is 'zhang'

注意：拼音教学在中国起步很晚，很多年长的中国人仍旧不会。w的用法和y的用法基本一样，但在与韵母u组音的时候wu没有特别之处，yu 读作【juiw】 w 【u：】声母 y 【i：】声母 wu【u:】 . yu 【juiw】 . yi【i:】 . wei【wi】 . you【Jo:】 . wo【wow】