
> The relatedness between the meaning of a compound [i.e. bisyllabic word] and those of its components can vary from close to nonexistent … For example, qūzú ‘to chase’ is composed of two morphemes from Classical Chinese … neither of which exists any longer as a morpheme in modern Mandarin.
That is, in many cases, the syllables of disyllabic Mandarin words are no longer synchronically analysable as morphemes, though at one point in the past it was possible to analyse them in this way. In this particular case, neither the character for qū nor the character for zú represents a morpheme, at least when used in this context.
Moser doesn't mention that Chinese grammar is trivial
He didn't say that, because Chinese is chock-full of difficult grammar. Take a look at the page count (847 pages) of the book A Grammar of Spoken Chinese by late Chinese linguist Yuen Ren Chao. His book is thorough, but by no means exhaustive. Li and Thompson's Mandarin Chinese: A Functional Reference Grammar (713 pages) is familiar to many English-speaking students of Chinese. It too is far from exhaustive. Many of the mistakes made in speaking standard Chinese by second-language speakers that impair understanding are GRAMMAR mistakes, and that is true even of native speakers of other Sinitic languages ("Chinese dialects") who don't know Modern Standard Chinese as a first language. And almost half the population of Chinese, according to a survey by the Chinese government, self-rates as unable to converse in Modern Standard Chinese.
http://news.xinhuanet.com/english/2007-03/07/content_5812838...
Moreover, despite what that article says, written Chinese characters are frequently a barrier to understanding among Chinese citizens from different regions too. There is first of all the problem of high rates of illiteracy in China, because of the old-fashioned writing system Moser mentions. Many literate Chinese persons tend to write in the regional vocabulary and grammar--there is that again--of their native Sinitic language when they write, and I have seen numerous occasions of Chinese people traveling out of region and not being able to read hand-written signs at markets or even printed official signs posted by the local government.