Khoekhoe language
Lexical root words consist of two or rarely three moras, in the form CVCV(C), CVV(C), or CVN(C). (The initial consonant is required.) The middle consonant may only be w r m n (w is b~p and r is d~t), while the final consonant (C) may only be p, s, ts. Each mora has tone, but the second may only be high or medium, for six tone "melodies": HH, MH, LH, HM, MM, LM.