Mandarin or Cantonese (7)
I believe the answer is:
chinese
'mandarin or cantonese' is the definition.
(I know that Beijing dialect is a type of Chinese)
This is all the clue.
(Other definitions for chinese that I've seen before include "- Chequers; - leaves; - puzzle" , "CIE hens from Beijing, say" , "Member of Han people" , "Boxes within boxes" , "in Eastern country" .)