Journal of Experimental Psychology: Learning, Memory, and Cognition Gradient Phonological Inconsistency Affects Vocabulary Learning

Learners frequently experience phonologically inconsistent input, such as exposure to multiple accents. Yet, little is known about the consequences of phonological inconsistency for language learning. The current study examines vocabulary acquisition with different degrees of phonological inconsistency, ranging from no inconsistency (e.g., both talkers call a picture /vig/) to mild but detectable inconsistency (e.g., one talker calls a picture a /vig/, and the other calls it a /vIg/), up to extreme inconsistency (e.g., the same picture is both a /vig/ and a /dId/). Previous studies suggest that learners readily extract consistent phonological patterns, given variable input. However, in Experiment 1, adults acquired phonologically inconsistent vocabularies more slowly than phonologically consistent ones. Experiment 2 examined whether word-form inconsistency alone, without phonological competition, was a source of learning difficulty. Even without phonological competition, listeners learned faster in 1 accent than in 2 accents, but they also learned faster in 2 accents (/vig/ ϭ /vIg/) than with completely different labels (/vig/ ϭ /dId/). Overall, results suggest that learners exposed to multiple accents may experience difficulty learning when 2 forms mismatch by more than 1 phonological feature, plus increased phonological competition due to a greater number of word forms. Implications for learning from variable input are discussed. A major challenge in language acquisition is identifying the relevant sources of variability in a complex signal. A listener hearing a novel language must rapidly determine which of numerous differences from sentence to sentence, or from word to word, indicate a change in meaning and which changes are irrelevant to meaning. Further, recent research indicates that high levels of variability can lead to language change (e. regularize their input, making morphosyntactic forms more consistent than their input would dictate (see also Kirby, Cornish, & Smith, 2008). However, most research on the role of variability in language acquisition has focused on morphosyntax and semantics, leaving open what happens in situations of phonological input variability. This is an important consideration, because most listeners experience some degree of phonological inconsistency within single word forms due to accent variability: Children in South Carolina must learn that their parents mentioning a pen (/pIn/) and a newscaster mentioning a pen (/pεn/) refer to the same object. Children whose parents are native Spanish speakers of English may hear their parents call a pen something closer to " pain " /peIn/ due to the different distributions of vowel sounds in English and Spanish (e.g., Fox, …