Cantonese

Cantonese was a dialect of Chinese that was spoken by Captain Chin Lee. The Third Doctor once had a brief conversation with her in the dialect. (TV: The Mind of Evil)

Behind the scenes
Chin Lee actor Pik Sen Lim actually spoke Hokkien natively, not Cantonese. (DOC: The Military Mind)

Cantonese is one of the few real world languages to be subtitled in televised Doctor Who, since it is generally assumed that the TARDIS translation circuits are naturally giving everyone in any given scene mutual intelligibility.