Spectral change and duration as cues in Australian English listeners' front vowel categorization

Australian English /i/, /I/, and /I∂/ exhibit almost identical average first (F1) and second (F2) formant frequencies and differ in duration and vowel inherent spectral change (VISC). The cues of duration, F1 × F2 trajectory direction (TD) and trajectory length (TL) were assessed in listeners' categorization of /i/ and /I∂/ compared to /I/. Duration was important for distinguishing both /i/ and /I∂/ from /I/. TD and TL were important for categorizing /i/ versus /I/, whereas only TL was important for /I∂/ versus /I/. Finally, listeners' use of duration and VISC was not mutually affected for either vowel compared to /I/.