The Role of Stimuli Perceptibility in Learning and Generalization of Phonological Patterns

Phonological patterns tend to be restrictive, often only applying to a subset of sounds in the language (e.g., height harmony applying only to front vowels). When given a limited input, what factors do learners use to determine if a novel sound participates in a phonological process? In two artificial language learning experiments, adult participants were exposed to a metathesis pattern where two stop consonants (from a six-consonant inventory) switched places with the fricative /f/ (e.g., /ep/ + /fu/ [efpu]), and were then tested on all six consonants. Participants who were only exposed to voiced or voiceless segments showed robust generalization, but participants exposed to only velar or only labial segments showed weaker generalization. In Experiment 2, a perception task revealed a significant correlation between perceptibility of the exposure items and generalization to novel consonants. These results support theories of phonology that are informed by phonetic properties of speech sounds.