Central vowels in Kamu and Larrakia

The vowel inventories of Kamu and Larrakia each consist of peripheral /i/-/u/-/e/-/a/-/o/ and another non-low vowel that has not been phonetically characterized. Descriptions of similar six-vowel systems in Western Top End languages offer inconsistent accounts of the non-peripheral vowel, but no instrumental analysis has yet been conducted. Acoustic and phonological analysis reveals that the sixth vowel is best characterized as /ʉ/ in Kamu and /ɨ/ in Larrakia. Height and backness are the critical phonetic properties that differentiate the non-peripheral vowel from the other vowel phonemes in each language. These results enhance our understanding of the structure and properties of higher cardinality vowel systems in Australian languages, and the typology of six-vowel systems more generally.