Explaining Individual Differences in Trajectories of Simultaneous Bilingual Development: Contributions of Child and Environmental Factors

Relations between early majority language and socioemotional development in children with different language backgrounds

This study explored whether the directionality of the relation between majority language and various facets of socioemotional development (three to 5 years old) differs between children with different language backgrounds. 12,951 children (49% girls; 85% White, 6% Pakistani and Bangladeshi, 3% Black, 3% Mix, 2% Indian) from the British Millennium Cohort Study (2001-2006) were included in two-time-point cross-lagged analyses. Models controlling for important covariates found a bidirectional association for monolinguals (βs = .05, -.07, -.04), a unidirectional effect of majority language on socioemotional difficulties for dual language learners (DLLs) speaking English and minority language(s) at home (β = .14), and a unidirectional effect of socioemotional strength on majority language for DLLs speaking only minority language(s) at home (β = -.17).

Child-level factors associated with Spanish-English bilingual toddlers' productive vocabulary growth

This longitudinal study-conducted in the Midwestern United States-examines the child-level factors that promote Spanish-English bilingual toddlers' (n = 47; Mage = 18.80 months; SDage = 0.57) productive vocabulary skills from 18 to 30 months of age. At 6-month intervals, caregivers reported on toddlers' Spanish and English words produced as well as their language exposure at home. Video recordings at child age 18 months yielded estimates of toddlers' speech output (word tokens per minute). In addition, at child age 18 months, caregivers reported on toddlers' linguistic skills (comprehension), demographic background (gender, household income), and nonverbal behaviors (gesture production). Results showed that toddlers were exposed to both English and Spanish and received more Spanish than English from primary caregivers; there were no significant primary caregiver input differences across time. Growth modeling revealed linear growth rates for Spanish and conceptual (Spanish, English combined) vocabulary and a curvilinear trajectory for English vocabulary. Furthermore, toddlers' Spanish and conceptual vocabularies were positively associated with their higher frequencies of token use, greater production of gesture, and greater comprehension skills, even after controlling for input. Moreover, Spanish and conceptual growth rates were positively associated with higher token use. In terms of English, toddlers' vocabulary at child age 18 months was positively associated with their comprehension skills. Toddlers' use of more gestures and tokens as well as gender (boys) influenced their English acceleration rates over time. Findings indicate that unique trajectories exist for each of a bilingual's languages and these trajectories are differentially influenced by child-level factors, including their speech output, not only exposure to language. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Effects of English versus Spanish language exposure on basic multisensory attention skills across 3 to 36 months of age

Recent research has demonstrated that individual differences in infant attention to faces and voices of women speaking predict language outcomes in childhood. These findings have been generated using two new audiovisual attention assessments appropriate for infants and young children, the Multisensory Attention Assessment Protocol (MAAP) and the Intersensory Processing Efficiency Protocol (IPEP). The MAAP and IPEP assess three basic attention skills (sustaining attention, shifting/disengaging, intersensory matching), as well as distractibility, deployed in the context of naturalistic audiovisual social (women speaking English) and nonsocial events (objects impacting a surface). Might children with differential exposure to Spanish versus English show different patterns of attention to social events on these protocols as a function of language familiarity? We addressed this question in several ways using children (n = 81 dual-language learners; n = 23 monolingual-language learners) from South Florida, tested longitudinally across 3-36 months. Surprisingly, results indicated no significant English language advantage on any attention measure for children from monolingual English versus dual English-Spanish language environments. Second, for dual-language learners, exposure to English changed across age, decreasing slightly from 3-12 months and then increasing considerably by 36 months. Furthermore, for dual-language learners, structural equation modeling analyses revealed no English language advantage on the MAAP or IPEP as a function of degree of English language exposure. The few relations found were in the direction of greater performance for children with greater Spanish exposure. Together, findings indicate no English language advantage for basic multisensory attention skills assessed by the MAAP or IPEP between the ages of 3 to 36 months. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Sources of individual differences in the dual language development of heritage bilinguals

Bilingual children are a more heterogenous group than their monolingual counterparts with respect to the sources of variation in their language learning environments, as well as the wide individual variation in their language abilities. Such heterogeneity in both individual difference factors and language abilities argues for the importance of an individual differences approach in research on bilingual development. The main objective of this article is to provide a review and synthesis of research on the sources of individual differences in the second language (L2) and heritage language (HL) development of child bilinguals. Several child-internal and child-external individual difference factors are discussed with respect to their influence on children's dual language abilities. In addition, the emergent research on individual differences in bilingual children with developmental language disorder is reviewed. Both the theoretical and applied relevance of individual difference approaches to bilingual development are discussed.

Commonalities, differences, and differences that matter between monolingual and bilingual development

This commentary makes the argument that the child-internal and child-external sources of individual differences in bilingual development are much the same as the sources of individual differences in monolingual development. It makes the further argument that the operation of the child-external influences results in differences between monolingual and bilingual development in the rate and sometimes in the outcome of language acquisition. An argument is made for the scientific and practical value of understanding the differences between monolingual and bilingual development, and future directions for research are suggested.

Effects of multilingualism on Australian infants' language environments in early childhood education centers

This study investigates differences in the language environments experienced by multilingual and monolingual infants in early childhood education and care (ECEC) settings. The Language Environment Analysis (LENA) technology was used to collect day-long audio-recordings from 181 one-year-old infants (age range from 12 to 21 months). We examined whether infants' multilingual status predicts the amount of educators' language input (adult word count, AWC), child vocalizations (CVC) and conversational turns (CTC), as well as interaction effects on AWC, CVC and CTC of infants' multilingual status and other infant, home and ECEC characteristics. Multilevel mixed effects models revealed no main effect of infants' multilingual status on the language environment outcome variables. Instead, infant gender significantly predicted adult word count, with female infants hearing more words from educators than male infants. There was a significant interaction effect between the infants' multilingual status and both their age and length of time in an ECEC setting on child vocalizations. While monolingual infants produced more vocalizations as their age increased, multilingual infants did not show this increase in vocalizations with age. Further, the difference between monolingual and multilingual children's vocalizations decreased as the length of time in ECEC increased. There were no significant predictors of conversational turns. Findings from this study suggest that early childhood educators do not adjust their talk according to the multilingual status of the infants. However, multilingual infants do not increase their vocalizations as their age increases to the same extent as do their monolingual peers. The interaction effect between multilingualism and the length of ECEC attendance also implies that ECEC environments may be particularly beneficial for supporting multilingual infants' vocalizations. This study highlights the need to provide pedagogical support to educators to help them to encourage multilingual infants' vocalizations in ECEC settings.

Cascades in language acquisition: Re-thinking the linear model of development

The first 5 years of life are characterized by incredible growth across domains of child development. Drawing from over 50 years of seminal research, this chapter contextualizes recent advances in language sciences through the lens of developmental cascades to explore complexities and connections in acquisition. Converging evidence-both classic and contemporary-points to the many ways in which advances in one learning system can pose significant and lasting impacts on the advances in other learning systems. This chapter reviews evidence in developmental literature from multiple domains and disciplines (i.e., cognitive, social, motor, bilingual language learning, and communication sciences and disorders) to examine the phenomenon of developmental cascades in language acquisition.

Predictors of language proficiency in school-age Spanish-English bilingual children with and without developmental language disorder

Children with developmental language disorder (DLD) have impairments in their language-learning abilities that may influence interactions with environmental opportunities to learn two languages. This study explores relationships between proficiency in L1 and L2 and a set of environmental and personal variables within a group of school-age Spanish-English bilingual children with DLD and a group of typically-developing peers. Within each group, current usage in the home, length of L2 exposure, gender, maternal education, analytical reasoning, and number of L1 conversational partners were used to predict proficiency in each language. Results showed that home language environment, particularly home L2 usage, strongly predicted L1 proficiency but had less influence on the L2. Female gender predicted L1 skills in both groups, whereas analytical reasoning predicted both L1 and L2 but only for children with DLD. This study expands the limited literature on how children with DLD interact with their environment to learn two languages.

Majority language skill, not measures of bilingualism, predicts executive attention in bilingual children

Evidence is mixed regarding whether and why bilingual children might be advantaged in the development of executive functions. Five preregistered hypotheses regarding sources of a bilingual advantage were tested with data from 102 Spanish-English bilingual children and 25 English monolingual children who were administered a test of executive attention, the flanker task, at 7, 8, and 9 years of age. Measures of the children's early and concurrent bilingual exposure and their concurrent English and Spanish skill were available from a larger longitudinal study in which these children participated. Tests of the preregistered hypotheses yielded null findings: The bilingual children's executive attention abilities were unrelated to their amount of early exposure to mixed input, to balance in their early dual language exposure, to balance in their concurrent exposure, to their degree of bilingualism, or to their combined Spanish + English vocabulary score. English vocabulary score was a positive significant correlate of executive attention among the bilingual children, but those bilingual children above the group median in English vocabulary did not outperform the monolingual children when the comparison was adjusted for nonverbal IQ. These findings suggest that a language learning ability may explain the association between bilingualism and executive function. Because the best statistical approach to testing for effects on differences is a matter of dispute, all analyses were conducted with both a difference score and a residual gain score as the outcome variable. The central findings, but not all findings, were the same with both approaches.

Within- and Cross-Language Relations Between Phonological Memory, Vocabulary, and Grammar in Bilingual Children

PURPOSE

This study investigated within-language and between-language associations between phonological memory, vocabulary, and grammar in French-English (n = 43) and Spanish-English (n = 25) bilingual children at 30, 36, and 48 months. It was predicted that phonological memory would display both within-language and between-language relations to language development and that these relations would be stronger at the youngest age.

METHOD

Bilingual children participated in free-play sessions in both of their languages at each age, from which vocabulary and grammatical information (number of different words and mean length of utterance) was extracted. Vocabulary information was also obtained from parent inventories completed when the children were 30 months and a standardized receptive vocabulary test administered at 36 and 48 months. The children were also administered nonword repetition tests in both of their languages at each age.

RESULTS

Mixed logistic regression indicated that phonological memory was associated with vocabulary and grammar within the same language and phonological memory in the other language. In two of the four statistical models, phonological memory exhibited positive between-language relations, and in one model, it exhibited negative between-language relations to language development. Results also indicated that within-language and between-languages effects remained constant, or between-language associations decreased during the age range studied.

CONCLUSION

Overall, the findings provide some support for cross-language associations between phonological memory and lexical and grammatical skills.

What Can Bilingual Children Tell Us About the Developmental Relationship Between Vocabulary and Grammar?

Strong correlations between vocabulary and grammar are well attested in language development in monolingual and bilingual children. What is less clear is whether there is any directionality in the relationship between the two constructs, whether it is predictive over time, and the extent to which it is affected by language input. In the present study, we analyzed data from 100 bilingual children with English as an additional language who were tested on measures of vocabulary breadth and depth, morphology, and syntax at three time points at 6-month intervals from the age of 5 and 8. We used bivariate growth models to test the directionality of the relationship between vocabulary breadth and depth, and measures of morphology and syntax; testing bilingual children allowed us to use measures of English input as covariates in the analyses. All the models showed a correlation between vocabulary and grammar, but no correlation between their growth slopes, suggesting that vocabulary and grammar grow independently. Three of the four bivariate models showed a significant correlation between the intercept of grammar skills and the slope of vocabulary growth. Length of exposure to English predicted the intercept of vocabulary breadth and grammar, suggesting that children exposed to English earlier had larger vocabularies and better morpho-syntactic skills. Current English input predicted the intercept of both measures of vocabulary as well as the slope for vocabulary depth, the only measure for which there was a significant relationship between intercept and slope, suggesting a Matthew effect for this dimension of vocabulary. All materials, data, and code are available at https://osf.io/vaq56/. Research highlights Vocabulary breadth and morphological and syntactic skills increased linearly for all participants, without any difference between lower and higher achieving children. Vocabulary depth grew more over time for those children with deeper vocabulary knowledge and higher levels of current English input at the start of the study. All of the bivariate growth models showed a correlation between vocabulary and grammar, but failed to show any correlation between their growth. Significant relationships between the intercept of grammar and the growth of vocabulary showed steeper lexical growth in children with better grammar skills. Length of exposure to English had an effect on morphological and syntactic skills, while only current English input had an effect on vocabulary depth.

Language acquisition in a multilingual society: English vocabulary norms and predictors in Singaporean children

In this study, infant vocabulary development was tracked in a multilingual society (Singapore) within a socioeconomically diverse sample. The sample comprised 1316 infants from 17.4 to 27.7 months (669 females, 647 males; 88% Chinese race, 4% Malay, 4% Indian, and 0.004% mixed-race [4% declined to provide race information]). Children varied in English language exposure and socioeconomic status. Analyses focused on identifying demographic predictors of English vocabulary size in multilingually exposed infants. Adaptations of the Macarthur-Bates Communicative Development Inventory for English, Mandarin, and Malay are provided as well as English vocabulary norms that account for variation in English exposure. This manuscript reports the first set of English language norms-calibrated to English exposure-for multilingual infants in a non-Western setting.

The Impact of Birth Order on Language Development in Autistic Children from Simplex Families

The current study investigated the impact of birth order on vocabulary and social language development in 1338 first-born and 1049 s-born autistic youth (M age = 9.03 years, SD = 3.57; 86.4% male) from the Simons Simplex Collection. Frequentist and Bayesian analyses revealed mixed findings in language development. There were no differences in vocabulary or social language between first-born and second-born children. However, birth order and income together predicted expressive vocabulary and inappropriate speech such that birth order had a greater impact on language in lower-income families. This is the first study to investigate the impact of birth order on language outcomes in autistic youth and has implications for early intervention in lower-resourced communities.

Variation in quality of maternal input and development of coda stops in English-speaking children in Singapore

This study examines the effects of input quality on early phonological acquisition by investigating whether interadult variation in specific phonetic properties in the input is reflected in the production of their children. We analysed the English coda stop release patterns in the spontaneous speech of fourteen mothers and compared them with the spontaneous production of their preschool children. The analysis revealed a very strong positive input-production relationship; mothers who released coda stops to a lesser degree also had children who tended to not release their stops, and the same was true for mothers who released their stops to a higher degree. The findings suggest that young children are sensitive to acoustic properties that are subphonemic, and these properties are also reflected in their production, showing the importance of considering input quality when investigating child production.

Profiles of Minority-Majority Language Proficiency in 5-Year-Olds

Children from language minority homes reach school age with variable dual language skills. Cluster analysis identified four bilingual profiles among 126 U.S.-born, 5-year-old Spanish-English bilinguals. The profiles differed on two dimensions: language balance and total language knowledge. Balance varied primarily as a function of indicators of the relative quantity and the quality of their language exposure (amount of home exposure and maternal education in each language). Total language knowledge varied primarily as a function of indicators of children's language learning ability (phonological memory and nonverbal intelligence). English dominance was more prevalent than balanced bilingualism; there was no Spanish dominant profile, despite average Spanish dominance in home language use. There was no evidence of a tradeoff between English and Spanish skills.

Why bilingual development is not easy

All normal children in normal environments acquire language. However, all normal children in normal bilingual environments do not acquire two languages. This chapter asks what makes the simultaneous acquisition of two languages more difficult than the acquisition of one. Focusing on children in immigrant families whose two languages are a minority language used more at home and a majority, societal language, this chapter describes common patterns and individual differences in bilingual development. The most frequently occurring outcome in that circumstance is strong skill in the majority language with more varied and weaker skills in the minority language. This chapter also reviews research that identifies factors that contribute to individual differences in order to identify the experiences and abilities that support bilingual development. Those factors include the quality and quantity of children's exposure to each language, children's use of each language, and the functional value of proficiency in each language. We conclude that two languages are more difficult to acquire than one because language acquisition requires substantial and continued environmental support. It is not easy for children to acquire strong and comparable skills levels in two languages because environments tend not to provide high and comparable levels of support for two languages.

A multidimensional approach to Spanish-English bilingual preschoolers' narrative skills

We identify language and discourse skills in 54-month-old Spanish-English bilingual preschoolers and their English-speaking monolingual peers, using multiple measures. Forty-one Spanish-English bilingual and 25 English monolingual children, all US born, viewed an eight-minute wordless video. The bilingual children recounted the story once in English and once in Spanish, in counterbalanced order. The story retellings were transcribed and coded for discourse skills (narrative length, narrative components and uses of evaluative language) and language skills (number of words, number of different words, MLUw). No difference was found in the two groupś overall language or discourse skills, assessed in the narrative production, with the exception of certain uses of evaluative language. Within the bilingual group, all measures, except MLUw, were highly correlated across the two languages. Our multidimensional analysis of narrative structure and use of evaluative language sheds light on certain differences between the ways in which English monolinguals and Spanish-English bilinguals organize their narrative discourse. We discuss the advantages of using this multidimensional approach in assessing bilingualś language and discourse abilities in narrative production.