What we know about what we have never heard: evidence from perceptual illusions.

Are speakers equipped with preferences concerning grammatical structures that are absent in their language? We examine this question by investigating the sensitivity of English speakers to the sonority of onset clusters. Linguistic research suggests that certain onset clusters are universally preferred (e.g., bd>lb). We demonstrate that such preferences modulate the perception of unattested onsets by English speakers: Monosyllabic auditory nonwords with onsets that are universally dispreferred (e.g., lbif) are more likely to be classified as disyllabic and misperceived as identical to their disyllabic counterparts (e.g., lebif) compared to onsets that are relatively preferred across languages (e.g., bdif). Consequently, dispreferred onsets benefit from priming by their epenthetic counterpart (e.g., lebif-lbif) as much as they benefit from identity priming (e.g., lbif-lbif). A similar pattern of misperception (e.g., lbif-->lebif) was observed among speakers of Russian, where clusters of this type occur. But unlike English speakers, Russian speakers perceived these clusters accurately on most trials, suggesting that the perceptual illusions of English speakers are partly due to their linguistic experience, rather than phonetic confusion alone. Further evidence against a purely phonetic explanation for our results is offered by the capacity of English speakers to perceive such onsets accurately under conditions that encourage precise phonetic encoding. The perceptual illusions of English speakers are also irreducible to several statistical properties of the English lexicon. The systematic misperception of universally dispreferred onsets might reflect their ill-formedness in the grammars of all speakers, irrespective of linguistic experience. Such universal grammatical preferences implicate constraints on language learning.