Electrophysiological Differentiation of the Effects of Stress and Accent on Lexical Integration in Highly Fluent Bilinguals

Abstract

Individuals who acquire a second language (L2) after infancy often retain features of their native language (L1) accent. Cross-language priming studies have shown negative effects of L1 accent on L2 comprehension, but the role of specific speech features, such as lexical stress, is mostly unknown. Here, we investigate whether lexical stress and accent differently modulate semantic processing and cross-language lexical activation in Welsh–English bilinguals, given that English and Welsh differ substantially in terms of stress realisation. In an L2 cross-modal priming paradigm, we manipulated the stress pattern and accent of spoken primes, whilst participants made semantic relatedness judgments on visual word targets. Event-related brain potentials revealed a main effect of stress on target integration, such that stimuli with stress patterns compatible with either the L1 or L2 required less processing effort than stimuli with stress incompatible with both Welsh and English. An independent cross-language phonological overlap manipulation revealed an interaction between accent and L1 access. Interestingly, although it increased processing effort, incorrect stress did not significantly modulate semantic priming effects or covert access to L1 phonological representations. Our results are consistent with the concept of language-specific stress templates, and suggest that accent and lexical stress affect speech comprehension mechanisms differentially.

Do accent and input modality modulate processing of language switches in bilingual language comprehension?

“…This could indicate that accent and input modality did not affect language coactivation (enough) in our experimental setups to modulate language competition and language control. This appears at odds with previous research showing that language-specific phonological and orthographic information can modulate language coactivation (see, e.g., Casaponsa et al, 2015;Lagrou et al, 2013;Lewendon, 2020;Orfanidou & Sumner, 2005). However, it is possible that the manipulations used in our Experiments 2 and 3 did influence language coactivation, but simply not sufficiently to influence competition and language control.…”

“…Importantly, because we wanted all participants (including those living in China) to be familiar with the accent the words were pronounced with, all words, including the English ones, were pronounced by an L1-Mandarin speaker. There is evidence that phonological information can influence the degree of language coactivation (e.g., Lagrou et al, 2011Lagrou et al, , 2013Lewendon, 2020). It is possible that the L1-Mandarin accent used on the L2-English words boosted the activation of L1-Mandarin throughout the task.…”

“…Together, this set of studies suggests that phonological information such as a speaker's accent may modulate coactivation of the nontarget language and language interference in the listener (e.g., Lewendon, 2020). In our Experiment 1, the fact that all words were produced by an L1-Mandarin speaker could have increased the activation of the nontarget L1-Mandarin language while processing the L2-English words, and in turn might have boosted the need for language control and increase or result in switching costs.…”

“…In Experiment 3, we examined the modality of word presentation (spoken or written). We chose accent and modality in particular as previous research suggests that both phonological and orthographic information may influence the degree of language coactivation (e.g., Lagrou et al, 2011Lagrou et al, , 2013Lewendon, 2020;Orfanidou & Sumner, 2005).…”

“…Very few studies, however, have examined whether accents modulate language activation (Lewendon, 2020), although some research suggests that phonological cues can influence the degree to which a bilingual's two languages are coactivated during language comprehension. For example, Ju and Luce (2004) found that including L2-English voice onset times at the beginning of L1-Spanish words (e.g., "playa") increased bilinguals' likelihood to look at pictures of cross-language English competitors (e.g., "pliers") during a Spanish visual world task.…”