Research ReportHyperarticulation of vowels enhances phonetic change responses in both native and non-native speakers of English: Evidence from an auditory event-related potential study

The finding that hyperarticulation of vowel sounds occurs in certain speech registers (e.g., infant- and foreigner-directed speech) suggests that hyperarticulation may have a didactic function in facilitating acquisition of new phonetic categories in language learners. This event-related potential study tested whether hyperarticulation of vowels elicits larger phonetic change responses, as indexed by the mismatch negativity (MMN) component of the auditory event-related potential (ERP) and tested native and non-native speakers of English. Data from 11 native English-speaking and 10 native Greek-speaking participants showed that Greek speakers in general had smaller MMNs compared to English speakers, confirming previous studies demonstrating sensitivity of the MMN to language background. In terms of the effect of hyperarticulation, hyperarticulated stimuli elicited larger MMNs for both language groups, suggesting vowel space expansion does elicit larger pre-attentive phonetic change responses. Interestingly Greek native speakers showed some P3a activity that was not present in the English native speakers, raising the possibility that additional attentional switch mechanisms are activated in non-native speakers compared to native speakers. These results give general support for models of speech learning such as Kuhl's Native Language Magnet enhanced (NLM-e) theory.

► We examined how the brains of native and non-native speakers of English process phonemically exaggerated speech sounds. ► We found that both native and non-native speakers process phonemically exaggerated stimuli equally. ► Phonemic exaggeration may be a ubiquitous and necessary process that facilitates learning of new speech sounds in the brain. ► Findings provide general support for Kuhl's native language magnet (enhanced) model of speech acquisition.