Does English fish sound like French fiche? Perceptual similarity judgments versus acoustic similarity

We examine the relationship between phonological word similarity judgments from listeners and acoustic measures of similarity. Native speakers of English or French with varying degrees of proficiency in the other language listened to pairs of words, one in French and the other in English. The words were highly phonologically similar but did not overlap in meaning. Participants judged how similar the items sounded. Each item pair was acoustically analyzed with six different acoustic distance metrics. The results demonstrate a weak correlation between the similarity judgments and five of the six acoustic distance measures. Within the experiment, we found an order of presentation effect: when the first word of a pair was in a participant's L1, the pair was rated more similar than if the first word was in the L2. This effect diminished in magnitude with increasing L2 proficiency. We discuss the implications of our results in light of theories of speech representation and processing.