Growing up around different accents: the effect of speech variability on infant word recognition

Parents' speech plays a crucial role in infants' language acquisition (Bruner, 1983). In many families, parents do not speak with the same accent. Different accents (regional or foreign) introduce speech variability, where the same word is pronounced in two different ways, meaning that the input received by the infant is inconsistent. Previous research presents conflicting findings as to the effect of this inconsistency on infants' language learning.

Infants are able to distinguish familiar and unfamiliar regional accents as early as at five months of age (Butler et al., 2010). The effect of this sensitivity to input variability, however, is unclear.

On one hand, exposure to different accents may facilitate understanding of other, unfamiliar accents. This has been shown in a number of lab-based studies where children from mono-accent backgrounds are briefly familiarised with a foreign accent, and then exposed to yet another unfamiliar accent. For example, 18-months-olds from an American English language background were better at recognising British English words after they had been exposed to Australian, Southern American and Indian English (Potter & Saffran, 2017). Moreover, brief exposure to a particular unfamiliar accent facilitates both word learning (Schmale et al., 2012) and word recognition (Paquette-Smith et al., 2020) in this accent.

Outside of the laboratory, when the exposure to two distinct accents happens from birth, Kartushina et al. (2021) showed that infants raised in bi-accent households are still better at learning novel words presented in unfamiliar accents. No conclusion, however, has been reached about familiar word recognition.

On the other hand, exposure to two different accents may delay word recognition. For example, two-year-olds exposed to both Canadian and a non-native English accent at home are worse at recognising words in Canadian English than infants from mono-accent backgrounds (Buckler et al., 2017). Infants exposed to two accents from birth are also less sensitive to word mispronunciations than infants from mono-accent environments (Durrant et al., 2015).

A discrepancy, therefore, emerges between studies manipulating accent exposure in the laboratory and those looking at multi-accent exposure from birth, regarding word recognition. This could either be due to a genuine difference between prolonged and brief multi-accent exposure or due to methodological differences.

All research on the topic to date has been based on behavioural measures. It is possible, however, to measure word recognition in infants using event-related potentials (ERP) data (Korpilahti et al., 2001). Adding ERP measures to the existing body of research could help reconcile any discrepancies that may arise from the differences in behavioural measures.

This project aims to systematically examine the effect of multi-accent exposure on infant word recognition by using a combination of behavioural and EEG measures. The study will consist of three phases, one examining word recognition in infants from mono- and multi-accent backgrounds, the next one introducing a manipulation of accent exposure in the laboratory, and the final one investigating whether exposure to regional and foreign accents variations modulate differently infants' word recognition skills. This will allow for a clear distinction between the effects of brief and prolonged exposure to more than one accent.