Auditory Disruption Improves Word Segmentation: A Functional Basis for Lenition Phenomena

This paper presents evidence that spirantization, a cross-linguistically common lenition process, affects English listeners’ ease of segmenting novel “words” in an artificial language. The cross-linguistically common spirantization pattern of initial stops and medial continuants (e.g. [ɡuβa]) results in improved word segmentation compared to the inverse “anti-lenition” pattern of initial continuants and medial stops (e.g. [ɣuba]). The study also tests the effect of obstruent voicing, another common lenition pattern, but finds no significant differences in segmentation performance. There are several points of broader interest in these studies. Most of the phonetic factors influencing word segmentation in past studies have been language-specific and/or prosodic in nature: stress, intonation, final lengthening, etc. Spirantization, while often prosodically conditioned, is different from all of these patterns in that it concerns a segmental alternation. Moreover, the effects reported here are for speakers of a language, American English, that only sporadically displays spirantization, and not in the phonological contexts used in the experiment. This suggests that the results may reflect more general properties of speech perception and word boundary detection, rather than a perceptual processing strategy transferred directly from English. As such, the studies offer partial support for theories of lenition rooted in notions of perceptual-acoustic continuity and disruption.