Unidentified beatboxing species (Men in Black II)

This alien race' s language consists a series of beatboxing. A member of this species was working at a post office in Massachusetts.  

Biology
Almost nothing is known about the physiology of this species, as its only known member was seen disguised as a human. However, when all the other aliens around him removed their disguises, the beatboxing alien merely stood around, and his species was recognized by scanning his Human face, leaving it possible that the Human appearance is the true appearance of the species.