The language or speech of a particular place, such as a country, region, village, or valley, especially:
a. Any of the Sinitic languages, such as Mandarin or Cantonese.
b. Any of the regional and local varieties of one of the Sinitic languages, such one of the dialects of Mandarin.
[topo- + (dia)lect (translation of Chinese (Mandarin) fāngyán, regional speech : fāng, place + yán, language).]