Vowel length is phonemic. /ɔː/ alone, deriving from proto-Selkup */aː/, has no short counterpart. The tenseness contrast, an innovation of northern Selkup, is independent of length (e.g. /i/, /iː/, /ɪ/, /ɪː/ all contrast). The full range of vowel quality contrasts is only possible in the initial syllable of a word: in later syllables, /e/ /ø/ /ɘ/ /y/ /ɨ/ of either length do not occur, nor does long /uː/.