How does one distinguish between Cantonese and Mandarin variations of Chinese?
ISO 639-2 was intended for written languages primarily, and since Chinese is the same in its written form for Cantonese and Mandarin, no distinction was made in the code list. . Individual Chinese languages included under the macrolanguage Chinese (coded as “zh” in 639-1; “zho” in 639-2/T and “chi” in 639-2/B) are listed at: http://www.sil.org/iso639-3/documentation.asp?id=zho. The ISO 639-3 code set defines cmn as Mandarin Chinese and yue as Yue Chinese (of which Cantonese is a dialect). Before the standardization of ISO 639-3 these could be coded by using the code for Chinese with the country code (i.e. zh-CN for Chinese as spoken in China and zh-TW for Chinese as spoken in Taiwan) or by using a subtag registered with the Internet Assigned Numbers Authority (IANA), (e.g. zh-guoyu).