Sources of illusion in consonant cluster perception

Previous studies have shown that listeners have difficulty discriminating between non-native CC sequences and licit alternatives (e.g. Japanese [ebzo]-[ebuzo], English [bnif]-[b=nif]) (Berent et al., 2007; Dupoux et al., 1999). Some have argued that the difficulty in distinguishing these illicit–licit pairs is due to a ‘‘perceptual illusion’’ caused by the phonological system, which prevents listeners from accurately perceiving a phonotactically unattested consonant cluster. In this study, we explore this and other sources of perceptual illusion by presenting English listeners with non-native word-initial clusters paired with various modifications, including epenthesis, deletion, C1 change, and prothesis, in both AX and ABX discrimination tasks (e.g. [zmatu]-[z=matu], [matu], [smatu], or [=zmatu]). For English listeners, fricative–initial sequences are most often confused with prothesis, stop–nasal sequences with deletion or change of the first consonant, and stop–stop sequences with vowel insertion. The pattern of results across tasks indicates that in addition to interference from the phonological system, sources of perceptual illusion include language-specific phonetic knowledge, the acoustic similarity of the stimulus items, the task itself, and the number of modifications to illicit sequences used in the experiment. & 2011 Elsevier Ltd. All rights reserved.