Blackfoot sounds

Consonants
Blackfoot has eighteen consonants, of which all but, , and  form pairs distinguished by length.

The velar consonants become palatals and  when preceded by front vowels.

Vowels
Blackfoot has a vowel system with three monophthongs,. Length is distinctive (áak o kaawa, "s/he will rope" vs. áak oo kaawa, "s/he will sponsor a sun dance"):

There are three additional vowels, called "diphthongs" in Frantz (1997). The first is pronounced before a long consonant,  (or, in the dialect of the Blackfoot Reserve) before  or , and  elsewhere (in the Blood Reserve dialect;  in the Blackfoot Reserve dialect). The second is pronounced before  and  elsewhere. The third is. The short monophthongs exhibit allophonic changes as well. and are raised to  and  respectively when followed by a long consonant, /i/ becomes  in closed syllables.

Blackfoot has a pitch accent system, meaning that every word has at least one high-pitched vowel, and high pitch is contrastive with non-high pitch (e.g.,  á pss i wa, "it's an arrow" vs.  a pss í wa, "it's a fig"). At the end of a word, non-high pitched vowels are devoiced.

Glides are deleted word-initially and after another consonant, e.g. in póósa 'cat' from poos-wa (cat-SG).