Victor Mair has an intriguing post at the Log, “Sayable but not writable,” about Chinese expressions that most Chinese don’t know how to write. Here’s the last couple of paragraphs:
I was also surprised that only a couple of the students from China had ever heard of, much less were able to write, the words gūlu 軲轆 (“wheel”) and gūlù 轂轆 (“reel”). These are old colloquial terms that seem to have survived mostly in the oral realm and are related to some form of the Indo-European word for “cycle; wheel”. See Robert S. Bauer, “Sino-Tibetan *kolo ‘Wheel’,” Sino-Platonic Papers 47 (Aug. 1994), 1-11.
I always tell the students in my classes that the sounds of the words in Chinese languages are much more important than the characters that might be used to write them — even in Classical Chinese — where there are often variant written forms for the same term. I demonstrated that for my students in the case of lāta 邋遢 (“slovenly; dirty; dowdy; sloppy; slobby; shaggy; unkempt; ill-groomed; sluttery; slipshod; untidy”) by putting on the board more than two dozen different topolectal variants of this colloquial term. I read aloud the pronunciations of each of the variants and pointed out that the second and subsequent characters of these variants were mostly arbitrary transcriptions of the sounds of the local variants and that the surface signification of the characters used to write these syllables was essentially irrelevant. The fact that many terms in Chinese — even in ancient texts — have a variety of different written forms, e.g., wěiyǐ 委迤 / wēiyí 委蛇 / wēiyí 逶迤 / etc. (“winding; meandering; twisting”) confirms the primacy of sound over symbol.
I was irresistibly reminded of a great anecdote in Jack Seward’s Japanese in Action about his going to considerable pains to learn the complicated Japanese character for ringo ‘apple’ to impress Japanese acquaintances only to discover that none of them knew it.