The perception of vowelless words in Tashlhiyt

Abstract

This study examines the perceptual mechanisms involved in the processing of words without vowels, a lexical form that is common in Tashlhiyt but highly dispreferred cross-linguistically. In Experiment 1, native Tashlhiyt and non-native (English-speaking) listeners completed a paired discrimination task where the middle segment of the different-pair was either a vowel (e.g., fan vs. fin), consonant (e.g., ʁbr vs. ʁdr), or vowelless vs. voweled contrast (e.g., tlf vs. tuf). Experiment 2 was a word-likeness ratings task of tri-segmental nonwords constructed to vary in the sonority of the middle segment. We find that vowelless words containing different types of sonority profiles were generally highly discriminable by both native and non-native listeners. This can be explained by the phonetic and acoustic properties of vowelless words: Since Tashlhiyt exhibits low consonant-to-consonant coarticulation, the presence of robust consonantal cues in the speech signal means that the internal phonological structure of vowelless words is recoverable by listeners. At the same time, word-likeness ratings of nonwords indicated that listeners relied on their native-language experience to judge the wellformedness of new words: Tashlhiyt listeners were most likely to accept obstruent-centered vowelless words; meanwhile, English listeners’ preferences increased with higher sonority values of the word center. Across both experiments, speech style variation provided further evidence as to how the phonetic implementation of vowelless words makes them perceptually stable. Thus, our findings provide an overview of the low-level acoustic-phonetic and higher-level phonological processing mechanisms involved in the perception of vowelless words. Our results can inform understandings of the relationship between language-specific phonetic variation and phonotactic patterns, as well as how auditory processing mechanisms shape phonological typology.