Very nice job! One potential customer/institution to cater to: western-based Chinese schools:
http://en.wikipedia.org/wiki/Chinese_schools, http://www.ncacls.org/ncacls_frm_intro.htm
These community based organizations often rely on eastern teaching methods (often rote) to instruct large numbers of young children. Your app would definitely introduce a different mindset (and fun!), when learning Chinese.
Btw, will you guys support different dialects (ie. cantonese)?