Previous research suggests that exposure to accent variability can affect toddlers' familiar word recognition and word comprehension. The current preregistered study addressed the gap in knowledge on early language development in infants exposed to two dialects from birth and assessed the role of dialect similarity in infants' word recognition and comprehension. A 12-month-old Norwegian-learning infants, exposed to native Norwegian parents speaking the same or two Norwegian dialects, took part in two eye-tracking tasks, assessing familiar word form recognition and word comprehension. Their parents' speech was assessed for similarity by native Norwegian speakers. First, in contrast to previous research, our results revealed no listening preference for words over nonwords in both monodialectal and bidialectal infants, suggesting potential language-specific differences in the onset of word recognition. Second, the results showed evidence for word comprehension in monodialectal infants, but not in bidialectal infants, suggesting that exposure to dialectal variability impacts early word acquisition. Third, perceptual similarity between parental dialects tendentially facilitated bidialectal infants' word recognition and comprehension. Forth, the results revealed a strong correlation between the raters and parents' assessment of similarity between dialects, indicating that parental estimations can be reliably used to assess infants' speech variability at home. Finally, our results revealed a strong relationship between word recognition and comprehension in monodialectal infants and the absence of such a relationship in bidialectal infants, suggesting that either these two skills do not necessarily align in infants exposed to more variable input, or that the alignment might occur at a later stage.
Keywords: dialect; infant; language development; speech variability; word comprehension; word recognition.
© 2022 The Authors. Developmental Science published by John Wiley & Sons Ltd.