An ERP investigation of accented isolated single word processing

Available online 18 August 2022Previous studies show that there are differences in native and non-native speech processing (Lev-Ari, 2018). However, less is known about the differences between processing native and dialectal accents. Is dialectal processing more similar to foreign or native speech? To address this, two theories have been proposed. The Perceptual Distance Hypothesis states that the mechanisms underlying dialectal accent processing are attenuated versions of those of foreign (Clarke & Garrett, 2004). Conversely, the Different Processes Hypothesis argues that the mechanisms of foreign and dialectal accent processing are qualitatively different (Floccia et al., 2009). The present study addresses these hypotheses. Electroencephalographic data was recorded from 25 participants who listened to 40 isolated words in different accents. Event-Related Potential mean amplitudes were extracted: P2 [150–250 ms], PMN [250–400 ms] and N400 [400–600 ms]. Support for the Different Processes Hypothesis was found in different time windows. Results show that early processing mechanisms distinguish only between native and non-native speech, with a reduced P2 amplitude for foreign accent processing, supporting the Different Processes Hypothesis. Furthermore, later processing mechanisms show a similar binary difference in the processing of the accents, with a larger PMN negativity elicited in the foreign accent than the others, further supporting the Different Processes Hypothesis. Results contribute to the understanding of single word processing, in which it is uniquely difficult to extract acoustic characteristics from foreign accent, and in which foreign accented speech is associated with the largest cost, as compared to native and dialectal speech, of phonological matching between representations and acoustic input.This work was supported by the Basque Government [BERC 2018–2021 program]; the Spanish State Research Agency [BCBL Severo Ochoa excellence accreditation SEV-2015-0490]; the H2020 European Research Council [ERC Consolidator Grant ERC-2018-COG-819093 to CDM; Marie Sklodowska-Curie grant 837228 to SC]; the Spanish Ministry of Economy and Competitiveness [PID 2020-113926 GB-I00 to CDM]; the Basque Government [PIBA18-29 to CDM]; the Italian Ministry of University and Research (Programma giovani ricercatori Rita Levi Montalcini) to SC; and the Programa Predoctoral de Formaci´on de Personal Investigador No Doctor del Departamento de Educaci´on del Gobierno Vasco (PRE_2021_2_0006 to TT)