Marieke van Heugten

Infants’ sensitivity to non-adjacent dependencies across phonological phrase boundaries

Natural languages contain numerous non-adjacent relationships between words or morphemes in a sentence, often straddling phonological phrase boundaries (e.g., [these sheep] [have [ellipsis (horizontal)]]). Since phonological phrases are considered the main processing unit for infants, this may cause the acquisition of cross-phrase dependencies to be challenging. This study, however, shows that by 17 months of age, French-learning infants have nonetheless gained sensitivity to remote determiner-auxiliary co-occurrences that are interceded by phonological phrase boundaries. Infants thus possess a robust mechanism for tracking non-adjacent dependencies. This ability is essential for early grammatical development.

The Developmental Trajectory of Toddlers’ Comprehension of Unfamiliar Regional Accents

Efficient language use involves the capacity to flexibly adjust to varied pronunciations of words. Although children can contend with some accent variability before their second birthday, it is currently unclear when and how this ability reaches its mature state. In a series of five experiments, we examine the developmental trajectory of toddlers’ comprehension of unfamiliar regional accents. Experiments 1 and 2 reveal that Canadian-English-learning 25-month-olds outperform their 20-month-old peers on the recognition of Australian-accented words and that this effect is likely driven by 25-month-olds’ larger vocabulary size. Experiments 3 to 5 subsequently show that 25-month-olds’ recognition of familiar words holds regardless of prior exposure to the speaker or accent. Taken together, these findings suggest that children’s ability to cope with accent variation improves substantially as their vocabulary expands in the second year of life and once it does, children recognize accented words on the fly, even without experience with the accent.

Toddlers' Word Recognition in an Unfamiliar Regional Accent: The Role of Local Sentence Context and Prior Accent Exposure

Adults are generally adept at recognizing familiar words in unfamiliar accents. However, studies testing young children’s abilities to cope with accent-related variation in the speech signal have generated mixed results, with some work emphasizing toddlers’ early competence and other work focusing more on their long-lasting difficulties in this domain. Here, we set out to unify these two perspectives and propose that task demands may play a crucial role in children’s recognition of accented words. To this end, Canadian-English-learning 28-month-olds’ looks to images on a screen were recorded while they were presented with a Scottish-accented speaker instructing them to find a depicted target object. To examine the effect of task demands, both local sentence context and prior accent exposure were manipulated. Overall, Canadian toddlers were found to recognize Scottish-accented words successfully, showing above-chance performance in the identification of words produced in an unfamiliar accent, even when target labels were presented in isolation. However, word recognition was considerably more robust when target words were presented in sentence context. Prior exposure to the unfamiliar Scottish accent in the laboratory did not modulate children’s performance in this task. Taken together, these findings suggest that at least some task-related factors can affect children’s recognition of accented words. Understanding unfamiliar accents, like understanding familiar accents, is thus not an isolated skill but, rather, is susceptible to contextual circumstances. Future models of spoken language processing in toddlerhood should incorporate these early effects of task demands.

Relative Difficulty of Understanding Foreign Accents as a Marker of Proficiency

Foreign-accented speech is generally harder to understand than native-accented speech. This difficulty is reduced for non-native listeners who share their first language with the non-native speaker. It is currently unclear, however, how non-native listeners deal with foreign-accented speech produced by speakers of a different language. We show that the process of (second) language acquisition is associated with an increase in the relative difficulty of processing foreign-accented speech. Therefore, experiencing greater relative difficulty with foreign-accented speech compared with native speech is a marker of language proficiency. These results contribute to our understanding of how phonological categories are acquired during second language learning.

Voice familiarity helps infants tackle variability in the speech signal.

The acoustic realization of lexical items produced by different speakers can vary greatly. Current research suggests that infants, unlike adults, struggle to cope with this lack of invariance in the realization of words. Although 7.5‐month olds are able to recognize words across different utterances when produced by speakers of the same gender with similar voices, they fail to do so when target words produced in a female voice are subsequently produced in a male voice [Houston and Jusczyk (2000)]. Note that all work in this area has used disembodied unfamiliar voices to test infants. In the current study, we ask whether infants might perform better under more ecologically valid conditions, i.e., when tested on familiar rather than unfamiliar voices. Using the headturn preference procedure, infants were familiarized with passages spoken by their mother. During the test phase, they were presented with their father’s voice producing isolated repetitions of familiarized target words. Preliminary results sugge...