Emma Libersky

Disfluencies are common in spontaneous language, and adults use filled pauses to anticipate “difficult” words. At the same time, disfluent instructors receive lower ratings of knowledge and credibility. We focus on the consequences of filled pauses for adults' statistical word learning. In Experiment 1, monolingual adults listened to recordings introducing them to two speakers: one who produced an elevated rate of filled pauses and one who did not. However, both speakers were fluent when producing novel words during learning. In Experiment 2, the speaker introductions were removed, and disfluencies preceded productions of some novel words during learning. Across experiments, participants demonstrated a preference for the fluent speaker and rated the fluent speaker more favorably. Critically, word learning performance was not impacted by fluency. These findings replicate prior work on the consequences of disfluent instruction and suggest that learner attitudes—but not statistical learning mechanisms—are sensitive to speaker fluency cues.

Purpose: Speech disfluencies are common in individuals who do not stutter, with estimates suggesting a typical rate of six per 100 words. Factors such as language ability, processing load, planning difficulty, and communication strategy influence disfluency. Recent work has indicated that bilinguals may produce more disfluencies than monolinguals, but the factors underlying disfluency in bilingual children are poorly understood. Method: We investigated the child, lexical, and syntactic factors associated with disfluencies in bilingual children who do not stutter during parent–child interactions. Forty-four Spanish–English bilingual parent–child dyads engaged in a play-based interaction. The children were 4–6 years old ( M = 62.3 months, SD = 6.96; 19 boys, range: 48.0–71.0). Children's language abilities ranged from clinically low (i.e., with a developmental language disorder) to typical. Results: Analyses revealed that children were more disfluent when they produced longer utterances. There was also a tendency for children with lower language skills to produce more disfluencies than children with higher language skills, when producing longer utterances. However, the mean lexical frequency of each utterance, the language of the utterance, and the child's language dominance were not associated with children's disfluency. Conclusions: These findings inform psycholinguistic models of fluent speech production and indicate that in bilingual children who do not stutter, disfluency is largely a reflection of utterance length. Children's overall language ability rather than language dominance was a more important contributor to disfluency in spontaneous speech. These findings have implications for assessment of bilingual children and for considerations of factors that may support or hinder disfluency in bilingual children who do and do not stutter.

Studies of learning indicate that presenting materials from multiple categories together (interleaving them) tends to yield better learning vs. presenting categories separately (blocking them). However, the impact of interleaving on language learning is mixed and has not been tested in the context of dual language learning. Here, we taught monolingual English-speaking adults vocabulary in German or Polish across two experiments, interleaving or blocking the languages. In Experiment 1, we observed a benefit of interleaving. Experiment 2 included a break midway through the task, and participants across conditions performed similarly. Our findings indicate that the interleaving advantage observed in other domains extends to dual language learning and may stem from a spacing effect. These findings have implications not only for theories of second language acquisition and dual language learning, but also for developing pedagogical approaches that optimize learning of multiple languages.

Purpose: In the current study, we examined the alignment of language choice of bilingual parent–child dyads in play-based interactions. Method: Forty-four bilingual Spanish–English parent–child dyads participated in a 10-min naturalistic free-play interaction to determine whether bilingual children and their parents respond to each other in the same language(s) across conversational turns and whether children's language ability and children's and parents' language dominance affect language alignment. Children's language ability was indexed by the Bilingual English–Spanish Assessment. Logistic regression was used to test the effects of children's language ability and children's and parents' language dominance on the alignment of language choice. Results: Results revealed that children and parents largely aligned their language choice and that children's and parents' language dominance, but not children's language ability, influenced alignment. Patterns of alignment differed between children and parents. Children aligned to their dominant language, and this was true for both English- and Spanish-dominant children. In contrast, English-dominant parents aligned equally to both languages, whereas Spanish-dominant parents aligned significantly more to Spanish. Conclusion: Together, these findings suggest that bilinguals' alignment of language choice is deeply sensitive to language dominance effects in both children and adults but that parents may also choose their language strategically in conversations with their children.

Codeswitching is a common feature of bilingual language practices, yet its impact on word learning is poorly understood. Critically, processing costs associated with codeswitching may extend to learning. Moreover, verbs tend to be more difficult to learn than nouns, and the challenges of learning verbs could compound with processing costs associated with codeswitching. In two Experiments, we taught 4–5‐year‐old bilingual children verbs (Experiment 1, N = 25, 13 girls, 69% white, 83% Hispanic) and nouns (Experiment 2, N = 29, 12 girls, 72% while, 68% Hispanic) within English‐only and Spanish‐English codeswitched learning contexts. Children's language ability across Spanish and English was modeled continuously, allowing us to test the impact of language ability on learning. Children learned novel words successfully in both experiments, with no difference between conditions. However, children with higher language ability demonstrated steeper learning rates l in the English‐only condition relative to the codeswitched condition in both Experiment 1 (standardized coefficient of 0.19) and Experiment 2 (standardized coefficient of 0.14). Our findings indicate that bilingual children can successfully learn both verbs and nouns in codeswitched contexts but learning is modulated by a child's language skills as well as the number of learning opportunities they have had.

Children born preterm are at an elevated risk of language delays compared to children born full-term. However, there is a dearth of research investigating language outcomes in premature children exposed to more than one language. There is also limited empirical evidence linking the quantity and quality of parent input and language outcomes in premature children and the strength of these relationships in bilingual contexts remains unknown. Therefore, the current study examined language skills, parent input, conversational turns, and their associations at 16 months to 36 months in monolingual and bilingual children born preterm. Nine English-speaking monolingual parent–child dyads, and nine Spanish–English bilingual parent–child dyads participated in parent–child interactions that occurred over time in play-based contexts. Results revealed that preterm monolingual and bilingual children exhibited similar language abilities at all time points assessed. While both monolingual and bilingual dyads engaged in a comparable number of conversational turns at 16 m, monolingual mothers produced more words than bilingual mothers during play. Significant associations were observed between children’s vocabulary skills and their ability to combine words within and across most time points. Notably, relationships between parental input, conversational turns, and language skills were limited to a significant association between conversational turns at 16 m and vocabulary skills at 24 m. Together, findings indicate that bilingual children born preterm acquire language on the same timeline as monolingual children born preterm. While it is crucial that the current work be replicated in larger samples of children born preterm, the current work is the first to compare relationships between children’s language outcomes and the quantity and quality of parental input in monolingual and bilingual contexts.

Prior work on bilingual memory has largely focused on working memory and less on autobiographical memory. In the present study, we tested the effect of bilingualism on autobiographical memory and examined whether an effect would be moderated or mediated by working memory. Spanish-English bilingual and English-only monolingual adults completed an autobiographical cued-recall task, as well as a working memory measure. Memories were coded for retrieval speed and propositional idea density. Bilingual status was associated with faster memory retrieval but did not affect propositional idea density. Better working memory was associated with slower memory retrieval but did not affect propositional idea density, nor did working memory moderate or mediate the effect of bilingualism. Together, these results indicate an effect of bilingualism on the speed of autobiographical memory retrieval that does not extend to autobiographical memory content and suggest that the effect of bilingualism is independent of the effect of working memory.