Word learning in 14-month-old monolinguals and bilinguals: Challenges and methodological opportunities

Infants can learn words in their daily interactions early in life, and many studies have demonstrated that they can also learn words from brief in-lab exposures. While most studies have included monolingual infants, less is known about bilingual infants’ word learning and the role that language familiarity plays in this ability. In this study we examined word learning in a large sample (up to N = 148) of bilingual and monolingual 14-month-olds using a preferential looking paradigm. Two novel words were presented within sentence frames in one language (single-language condition) or two languages (dual-language condition). We predicted that infants would learn both words, and would exhibit better learning when they were more familiar with the sentence frame language. Using a traditional analytic approach (t-tests) and a standard linear regression, we found weak evidence that children learned one of the two words. However, contrary to our prediction, in a minority of conditions infants may have learned better when stimuli were presented in sentence frames in a less familiar language. We also conducted updated analyses using mixed-effects linear regression models, which did not support the conclusion that infants learned any of the words they encountered, regardless of the familiarity of the sentence frame language. We discuss these results in relation to prior work and suggest how open science practices can contribute to more reliable findings about early word learning

A multilab study of bilingual infants: Exploring the preference for infant-directed speech

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) compared with adult-directed speech (ADS). Yet IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multisite study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the multilab ManyBabies 1 project, we compared preference for North American English (NAE) IDS in lab-matched samples of 333 bilingual and 384 monolingual infants tested in 17 labs in seven countries. The tested infants were in two age groups: 6 to 9 months and 12 to 15 months. We found that bilingual and monolingual infants both preferred IDS to ADS, and the two groups did not differ in terms of the overall magnitude of this preference. However, among bilingual infants who were acquiring NAE as a native language, greater exposure to NAE was associated with a stronger IDS preference. These findings extend the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger IDS preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes similar contributions to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments

Word learning in 14-month-old monolinguals and bilinguals: Challenges and methodological opportunities

Infants can learn words in their daily interactions early in life, and many studies have demonstrated that they can also learn words from brief in-lab exposures. While most studies have included monolingual infants, less is known about bilingual infants’ word learning and the role that language familiarity plays in this ability. In this study we examined word learning in a large sample (up to N = 148) of bilingual and monolingual 14-month-olds using a preferential looking paradigm. To support word learning, novel words were presented within sentence frames in one language (single-language condition) or two lan-guages (dual-language condition). We predicted that infants would exhibit greater word–object learning when they were more familiar with the language of the sentence frame. Using both traditional (t-tests) and updated (linear mixed-effects models) analyses, we found limited evidence for successful word learning. Familiarity had little effect on word learning, and in two conditions where it did have an effect, this was in the opposite direction as predicted. Our results suggest that word learning in experimental settings can be challenging for 14-month-olds, even when sentence frames are provided. We discuss these results in relation to prior work and suggest how open science practices can contribute to more reliable findings about early word learning

Bilingualism affects infant cognition: Evidence from new and reanalyzed data

Bilingualism has been hypothesized to shape domain-general cognitive abilities across the lifespan, in what some have called the “bilingual advantage”. Here, we examined the replicability of a seminal study that showed monolingual–bilingual differences in infancy (Kovács & Mehler, 2009a) by collecting new data from 7-month-olds and 20-month-olds and reanalyzing three open datasets from 7–9 month-olds (D’Souza et al., 2020, Experiment 1; Kalashikova et al., 2020, Visual and Auditory conditions). All infants (total N = 181) were tested in an anticipatory eye movement paradigm, where they learned to use a visual and/or auditory cue to anticipate a visual reward presented consistently on one side of a screen during training, and on the opposite side of the screen at test. To correctly anticipate the reward at test, infants had to update their previously learned behavior. Across 3 out of 4 studies, results from a new analytic approach showed that 7–9 month-old bilinguals were better able to update the previously-learned response at test (a “bilingual advantage”), which could be related to bilinguals’ weaker initial learning of the contingency during the learning phase (a “monolingual advantage”). At 20 months, bilinguals performed better at test, though groups showed similar performance during the learning phase. Overall, these results show that bilingualism affects how infants process both new and updated information during learning

Sometimes larger, sometimes smaller: Measuring vocabulary in monolingual and bilingual infants and toddlers

Vocabulary size is a crucial early indicator of language development, for both monolingual and bilingual children. Assessing vocabulary in bilingual children is complex because they learn words in two languages, and there remains significant controversy about how to best measure their vocabulary size, especially in relation to monolinguals. This study compared monolingual vocabulary to different metrics of bilingual vocabulary, including combining vocabulary across languages to count either the number of words or the number of concepts lexicalized, and assessing vocabulary in a single language. Data were collected from parents of 743 infants and toddlers aged 8–33 months learning French and/or English, using the MacArthur-Bates Communicative Development Inventories. Results showed that the nature and magnitude of monolingual–bilingual differences depended on how bilinguals’ vocabulary was measured. Compared to monolinguals, bilinguals had larger expressive and receptive word vocabularies, similarly-sized receptive concept vocabularies, and smaller expressive concept vocabularies. Bilinguals’ single-language vocabularies were smaller than monolinguals’ vocabularies. The study highlights the need to better understand the role of translation equivalents in bilingual vocabulary development and the potential developmental differences in receptive and expressive vocabularies

Bilingualism affects infant cognition: Insights from new and open data

Bilingualism has been hypothesized to shape cognitive abilities across the lifespan. Here, we examined the replicability of a seminal study that showed monolingual–bilingual differences in infancy (Kovács & Mehler, 2009a) by collecting new data from 7-month-olds and 20-month-olds and reanalyzing three open datasets from 7–9 month-olds (D’Souza et al., 2020; Kalashikova et al., 2020; 2021). Infants from all studies (N = 222) were tested in an anticipatory eye-tracking paradigm, where they learned to use a cue to anticipate a reward presented on one side of a screen during Training, and the opposite side at Test. To correctly anticipate the reward at Test, infants had to update their previously learned behavior. Across 4 out of 5 studies, a fine-grained analysis of infants’ anticipations showed that bilinguals were better able to update the previously-learned response at Test, which could be related to bilinguals’ weaker initial learning during Training. However, in one study of 7-month-olds, we observed the opposite pattern: bilinguals performed better during Training, and monolinguals performed better at Test. These results show that bilingualism affects how infants process information during learning. We also highlight the potential of open science to advance our understanding of language development

Word learning in 14-month-old monolinguals and bilinguals: Challenges and methodological opportunities

Infants can learn words in their daily interactions early in life, and many studies have demonstrated that they can also learn words from brief in-lab exposures. While most studies have included monolingual infants, less is known about bilingual infants’ word learning and the role that language familiarity plays in this ability. In this study we examined word learning in a large sample (up to N = 155) of bilingual and monolingual 14-month-olds using a preferential looking paradigm. To support word learning, novel words were presented within sentence frames in one language (single-language condition) or two languages (dual-language condition). We predicted that infants would exhibit greater word–object learning when they were more familiar with the language of the sentence frame. Using both traditional (t-tests) and updated (linear mixed-effects models) analyses, we found no evidence for successful word learning, nor an effect of familiarity. Our results suggest that word learning in experimental settings can be challenging for 14-month-olds, even when sentence frames are provided. We discuss these results in relation to prior work and suggest how open science practices can contribute to more reliable findings about early word learning

How open science can benefit bilingualism research: A lesson in six tales

Bilingualism is hard to define, measure, and study. Sparked by the “replication crisis” in the social sciences, a recent discussion on the advantages of open science is gaining momentum. Here, we join this debate to argue that bilingualism research would greatly benefit from embracing open science. We do so in a unique way, by presenting six fictional stories that illustrate how open science practices – sharing preprints, materials, code, and data; pre registering studies; and joining large-scale collaborations – can strengthen bilingualism research and further improve its quality