BBOS has plenty serious issues on Chinese inputting. The unsolvable one, which is bothering me, is the word substitution doesn't work in Chinese, but it is all good in English. I know RIM didn't pay attention to Chinese market, otherwise they won't be in such an awkward situation, however, there are still lots of Chinese BBers, if this bug can be fixed somehow, it will be the best.
If you want to test it, the easiest way is to switch your input language to Chinese, then type "bb", if it works, "blackberry" should be one of the shortlist.