How many letters are there in the Cheyenne alphabet?

There is no native Cheyenne alphabet, since historically they had no writing system just like all of the Plains tribes. Pictographs and symbols were painted on buffalo hides and clothing, but this is not any kind of alphabet.

Modern attempts to set out the sounds of the Cheyenne language using English letters produced an alphabet of 3 vowels (a,e and o) and 11 consonants (h, k, ', m, n, p, s, sh, t, v and x). There are also stress marks and whisper marks that influence the way Words are pronounced. This alphabet has been used since 1971 in dictionaries, grammars and other books used in teaching the Cheyenne language.

A good starting point for learning Cheyenne is the English-Cheyenne Student Dictionary published in 1976 by the Northern Cheyenne Language and Cultural Centre, Lame Deer, Montana.