Ingrid at Language on the Move has some thoughtful comments on the relationship between height and learning English in China. If you're under 1.6 meters, forget it. There are subtle but very real socioeconomic barriers in your way. Money quote:
I have supervised research related to English language learning and teaching in China for almost a decade and have read most of the research on the topic published in English. However, never before have I come across the importance of height. I take this as evidence for the importance of doing ethnographic research. Otherwise, what is the point of doing sociolinguistic research if you can’t discover anything you hadn’t already decided in advance would be important?!
I taught EFL in China back in 1998 at a private school in Guangzhou catering mostly to working professionals. Much has changed since then, as China has changed so much. I don't recall ever talking about height as a factor, but certainly cost and hours were a significant issue that made it virtually impossible for any poor workers to consider taking English classes. As a 6 foot 4 blond American, though, I was treated like a rock star. It was kinda weird.