Convergence and divergence in prediction from vocabulary and speed of word processing.

Toddler vocabulary knowledge and speed of word processing are associated with downstream language and cognition. Here, we investigate whether these associations differ across measures. At age two, 101 participants (55 monolingual French-speaking and 46 monolingual English-speaking children) completed a two-alternative forced choice task, yielding measures of decontextualized vocabulary (number of correct responses) and haptic speed of word processing (latency of correct responses). At ages three, four, and five children completed a battery of language assessments and an executive function task. Growth curve models revealed that age-two vocabulary significantly predicted age-three performance (but not growth from age three to four or four to five) across all language assessments but speed of processing did not predict language outcomes in final models. Finally, speed of processing was correlated with executive function at age three whereas vocabulary was not. Results suggest that vocabulary is associated with a range of downstream language abilities whereas haptic speed of processing may be associated with executive control.

Visual and haptic responses as measures of word comprehension and speed of processing in toddlers: Relative predictive utility.

Early vocabulary knowledge and speed of word processing are important foundational skills for the development of preschool and school-age language and cognition. However, the variance in outcomes accounted for by parent-reported receptive or expressive vocabulary is generally modest. Recent research suggests that directly assessed, decontextualized vocabulary predicts developmental outcomes, including general language ability and kindergarten readiness, accounting for additional variance above and beyond parent-reported vocabulary. The current research extends this finding by exploring prediction from both decontextualized vocabulary and speed of word processing at 2 years of age to vocabulary during the preschool period. At age 2, children completed a two-alternative forced-choice task that yielded a measure of decontextualized vocabulary (number of correct touch responses) and two measures of speed of processing: latency to fixate the target (visual response latency) and latency to touch (haptic response latency). Results reveal that age 2 vocabulary and visual response latency, but not haptic response latency, independently predict vocabulary at ages 3 and 4. Furthermore, only decontextualized vocabulary remains a significant predictor when controlling for speed of processing, but not vice versa. This suggests that the number of early, stable word-referent associations and the efficiency with which these are processed are important to vocabulary outcomes. However, it also suggests that decontextualized vocabulary may be a more robust unique predictor of downstream outcomes.

The organization of words and environmental sounds in the second year: Behavioral and electrophysiological evidence.

The majority of research examining early auditory-semantic processing and organization is based on studies of meaningful relations between words and referents. However, a thorough investigation into the fundamental relation between acoustic signals and meaning requires an understanding of how meaning is associated with both lexical and non-lexical sounds. Indeed, it is unknown how meaningful auditory information that is not lexical (e.g., environmental sounds) is processed and organized in the young brain. To capture the structure of semantic organization for words and environmental sounds, we record event-related potentials as 20-month-olds view images of common nouns (e.g., dog) while hearing words or environmental sounds that match the picture (e.g., "dog" or barking), that are within-category violations (e.g., "cat" or meowing), or that are between-category violations (e.g., "pen" or scribbling). Results show both words and environmental sounds exhibit larger negative amplitudes to between-category violations relative to matches. Unlike words, which show a greater negative response early and consistently to within-category violations, such an effect for environmental sounds occurs late in semantic processing. Thus, as in adults, the young brain represents semantic relations between words and between environmental sounds, though it more readily differentiates semantically similar words compared to environmental sounds.

The relation between phonological and lexical development in French-speaking children.

This study examines the relation between lexical and phonological variables in 40 French-speaking children, aged 2;5. Specifically, it examines the influence of phonetic complexity, phonological production, phonological memory and neighbourhood density (ND) on vocabulary size. Children were divided into four groups on the basis of their scores on the French version of the Communicative Developmental Inventory (CDI): late1 (< 10%ile), late2 (15-25%ile), middle (40-60%ile) and precocious (> 90%ile). The children's lexicons were coded in terms of phonetic complexity and ND (one-and two-syllable words), and their production capacities were determined from measuring percent consonants correct (PCC) and the number of syllable-initial (CSI) and -final (CSF) consonants in their phonetic inventories. The children also took part in a non-word repetition (NWR) task. Results indicated significant group differences in all four sets of variables. Children with larger vocabularies selected words with greater phonetic complexity and with lower ND values. They had superior PCC, CSI and NWR scores compared to children with smaller vocabularies. Linear regression analyses indicated that 76% of variance in vocabulary size could be accounted for by ND in combination with phonetic complexity and CSI. Our findings are consistent with previous studies which show that ND plays an important role in accounting for variance in vocabulary size. They also indicate that phonetic complexity and phonological production influence lexical acquisition.

Assessing a continuum of lexical-semantic knowledge in the second year of life: A multimodal approach.

Behavioral dissociations in young children's visual and haptic responses have been taken as evidence that word knowledge is not all-or-none but instead exists on a continuum from absence of knowledge, to partial knowledge, to robust knowledge. This longitudinal study tested a group of 16- to 18-month-olds, 6months after their initial visit, to replicate results of partial understanding as shown by visual-haptic dissociations and to determine whether partial knowledge of word-referent relations can be leveraged for future word recognition. Results show that, like 16-month-olds, 22-month-olds demonstrate behavioral dissociations exhibited by rapid visual reaction times to a named referent but incorrect haptic responses. Furthermore, results suggest that partial word knowledge at one time predicts the degree to which that word will be understood in the future.

Developmental changes in maternal education and minimal exposure effects on vocabulary in English- and Spanish-learning toddlers.

The current research follows up on two previous findings: that children with minimal dual-language exposure have smaller receptive vocabularies at 16months of age and that maternal education is a predictor of vocabulary when the dominant language is English but not when it is Spanish. The current study extends this research to 22-month-olds to assess the developmental effects of minimal exposure and maternal education on direct and parent-report measures of vocabulary size. The effects of minimal exposure on vocabulary size are no longer present at 22months of age, whereas maternal education effects remain but only for English speakers.

Dog or chien? Translation equivalents in the receptive and expressive vocabularies of young French-English bilinguals.

In order to address gaps in the literature surrounding the acquisition of translation equivalents (TEs) in young bilinguals, two experiments were conducted. In Experiment 1, TEs were measured in the expressive vocabularies of thirty-four French-English bilinguals at 1;4, 1;10, and 2;6 using the MacArthur Bates CDI. Children's acquisition of TEs occurred gradually, with more balanced ratios of exposure and vocabulary associated with larger proportions of TEs at each wave. Experiment 2 compared a direct measure of TE comprehension with parent report of the same set of words. Results showed that parents may over-report children's TE comprehension, as our sample of two-year-old French-English bilinguals (n = 20) comprehended fewer TEs on a direct measure of receptive vocabulary than parents reported on the vocabulary checklist. The present study provides an original contribution to the literature on bilingual vocabulary development by employing both a longitudinal design and a direct measure of TE comprehension.

The effects of bilingual growth on toddlers' executive function.

The mastery of two languages provides bilingual speakers with cognitive benefits over monolinguals, particularly on cognitive flexibility and selective attention. However, extant research is limited to comparisons between monolinguals and bilinguals at a single point in time. This study investigated whether growth in bilingual proficiency, as shown by an increased number of translation equivalents (TEs) over a 7-month period, improves executive function. We hypothesized that bilingual toddlers with a larger increase of TEs would have more practice in switching across lexical systems, boosting executive function abilities. Expressive vocabulary and TEs were assessed at 24 and 31 months of age. A battery of tasks, including conflict, delay, and working memory tasks, was administered at 31 months. As expected, we observed a task-specific advantage in inhibitory control in bilinguals. More important, within the bilingual group, larger increases in the number of TEs predicted better performance on conflict tasks but not on delay tasks. This unique longitudinal design confirms the relation between executive function and early bilingualism.

Vocabulary size, translation equivalents, and efficiency in word recognition in very young bilinguals.

The present study examined early vocabulary development in fifty-nine French monolingual and fifty French-English bilingual infants (1;4-1;6). Vocabulary comprehension was assessed using both parental report (MacArthur-Bates Communicative Development Inventory; CDI) and the Computerized Comprehension Task (CCT). When assessing receptive vocabulary development using parental report, the bilinguals knew more words in their L1 versus their L2. However, young bilinguals were as accurate in L1 as they were in L2 on the CCT, and exhibited no difference in speed of word comprehension across languages. The proportion of translation equivalents in comprehension varied widely within this sample of young bilinguals and was linked to both measures of vocabulary size but not to speed of word retrieval or exposure to L2. Interestingly, the monolinguals outperformed the bilinguals with respect to accuracy but not reaction time in their L1 and L2. These results highlight the importance of using multiple measures to assess early vocabulary development.

Looking and touching: what extant approaches reveal about the structure of early word knowledge.

The goal of the current study is to assess the temporal dynamics of vision and action to evaluate the underlying word representations that guide infants' responses. Sixteen-month-old infants participated in a two-alternative forced-choice word-picture matching task. We conducted a moment-by-moment analysis of looking and reaching behaviors as they occurred in tandem to assess the speed with which a prompted word was processed (visual reaction time) as a function of the type of haptic response: Target, Distractor, or No Touch. Visual reaction times (visual RTs) were significantly slower during No Touches compared to Distractor and Target Touches, which were statistically indistinguishable. The finding that visual RTs were significantly faster during Distractor Touches compared to No Touches suggests that incorrect and absent haptic responses appear to index distinct knowledge states: incorrect responses are associated with partial knowledge whereas absent responses appear to reflect a true failure to map lexical items to their target referents. Further, we found that those children who were faster at processing words were also those children who exhibited better haptic performance. This research provides a methodological clarification on knowledge measured by the visual and haptic modalities and new evidence for a continuum of word knowledge in the second year of life.

Using Parent Report to Measure Vocabulary in Young Bilingual Children: A Scoping Review.

A large number of children are exposed to more than one language. One well-established method of assessing early vocabulary development in monolingual children is parent report; however, its use in bilingual/multilingual contexts is less established and brings unique challenges. In this methodological scoping review, we reviewed studies of early vocabulary development using parent report with bilingual/multilingual children (January 1980-March 2022). A total of 576 articles were screened, yielding 101 studies for analysis. The number of studies on bilingual/multilingual vocabulary has grown in the last two decades; yet representation of the world's languages remains sparse. The majority of studies assessed bilingual/multilingual children's vocabulary in each language and used instruments adapted for linguistic and cultural characteristics. However, the field could benefit from standardized reporting practices regarding definitions of bi/multilingualism, selection of reporters, and tool development and is in critical need of studies that develop, validate, and norm parent report instruments specifically for the bilingual/multilingual case.

Event-related potentials to intact and disrupted actions in children and adults.

The current research used event-related potentials (ERPs) to investigate neurophysiological responses to intact and disrupted actions embedded within an event in children and adults. Responses were recorded as children (24-month-olds) and adults observed a relatively novel event composed of three actions. In one condition pauses were inserted at intact boundaries (i.e., at the endpoint of each action), whereas in the other condition they were inserted at breakpoints that disrupted the action (i.e., in the middle of each action). Evoked responses revealed differences across conditions in both groups; disrupted actions elicited a prolonged negative slow wave from 100 to 700 ms in children, whereas adults demonstrated two distinct negative peaks between 50-150 and 250-350 ms. These findings contribute the first electrophysiological evidence that children readily detect disruptions to ongoing events by the end of the second year, even with limited exposure to the event itself. Furthermore, they suggest that adults rely on two distinct mechanisms when processing novel events. Results are discussed in relation to the role of perceptual and conceptual levels of analysis in the development of action processing.

Maternal education revisited: Vocabulary growth in English and Spanish from 16 to 30 months of age.

This paper reports on a cross-language longitudinal study in which we extend previous research on the effects of maternal education on vocabulary growth in Spanish- and English-dominant children at three time points: 16 months, 22 months, and 30 months of age. This study addresses recent conflicting evidence regarding the role of maternal education in children's acquisition of Spanish. Participants were 62 English-dominant children, 47 Spanish-dominant children, and their mothers. Growth curve models were constructed separately for English and Spanish vocabulary. Strong growth rate reliability and effect sizes were evinced for vocabulary across samples. As expected, in English-dominant children, maternal education predicted English vocabulary and growth from 16 to 30 months of age. However, in Spanish-dominant children, there was no significant effect of maternal education on vocabulary or growth, although there was a descriptive advantage for children of college-educated mothers at 30 months of age. In conjunction with prior evidence, we conclude that the effect of maternal education on maternal input and child vocabulary does not generalize readily to children whose first language is Spanish. Our findings contribute to a literature that suggests that focusing on maternal beliefs, input, and the home literacy environment are more fruitful approaches in the study of children learning Spanish in the U.S. Further, the importance of maternal beliefs highlights the need to support parent investment in the quantity and quality of input in the home language.

A Longitudinal Assessment of the Home Literacy Environment and Early Language.

This longitudinal assessment concentrated on the relation between the Home Literacy Environment (HLE) and early language acquisition during infancy and toddlerhood. In Study 1, after controlling for SES, a broadly-defined HLE predicted language comprehension in 50 infants. In Study 2, 27 children and their primary caregivers returned for further analyses. Findings revealed that the HLE measured in infancy predicted language production in toddlerhood, and maternal redirecting behaviors measured in toddlerhood were negatively associated with expressive language. Results across both studies indicate the importance of a broadly-defined HLE (including joint attention and parent-child conversation) for language development. Taken together, these findings highlight the importance of the HLE in supporting both receptive and expressive vocabulary growth in the second and third years of life.

Relations between phonological production, grammar and the lexicon in bilingual French-English children.

AIMS AND OBJECTIVES: This study examines multiple associations between language domains in bilingual children with a focus on phonology. Previous studies indicate within- but not cross-language associations between vocabulary and grammar in bilingual children. We investigate whether the relation between phonology and other language domains differs from the one reported between vocabulary and grammar. METHODOLOGY: Canadian French-English bilingual children (n = 31), aged 31 months, participated in 2 free-play sessions, from which lexical, grammatical and phonological information was extracted. The children's parents completed the MacArthur-Bates Communicative Developmental Inventories and its Canadian French adaptation providing additional information on vocabulary and grammar in each of the children's languages. They also completed a questionnaire on their children's exposure to French and English. DATA ANALYSIS: Within and cross-language relations between phonology, vocabulary and grammar were investigated using correlational analyses and mixed logistic regression. FINDINGS: Correlational analyses did not reveal significant cross-language relations between phonology, vocabulary and grammar. However, mixed logistic regression, which controlled for language exposure effects, indicated that phonology was influenced by vocabulary and grammar both within and across languages. ORIGINALITY: This study is one of the first to study cross-domain relations involving phonology in young bilingual children. IMPLICATIONS: Overall, the findings suggest that phonology displays a pattern of relations that is different from other language domains engendering between-language effects due to a language-general component.

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.

Lexical-Semantic Development in Bilingual Toddlers at 18 and 24 Months.

An important question in early bilingual first language acquisition concerns the development of lexical-semantic associations within and across two languages. The present study investigates the earliest emergence of lexical-semantic priming at 18 and 24 months in Spanish-English bilinguals (N = 32) and its relation to vocabulary knowledge within and across languages. Results indicate a remarkably similar pattern of development between monolingual and bilingual children, such that lexical-semantic development begins at 18 months and strengthens by 24 months. Further, measures of cross-language lexical knowledge are stronger predictors of children's lexical-semantic processing skill than measures that capture single-language knowledge only. This suggests that children make use of both languages when processing semantic information. Together these findings inform the understanding of the relation between lexical-semantic breadth and organization in the context of dual language learners in early development.

The Relationship Between Lexical and Phonological Development in French-Speaking Children: A Longitudinal Study.

Purpose This study examines the influence of lexical and phonological factors on expressive lexicon size in 40 French-speaking children tested longitudinally from 22 to 48 months. The factors include those based on the lexical and phonological properties of words in the children's lexicons (phonetic complexity, word length, neighborhood density [ND], and word frequency [WF]) as well as variables measuring phonological production (percent consonants correct and phonetic inventory size). Specifically, we investigate the relative influence of these factors at individual ages, namely, 22, 29, 36, and 48 months, and which factors measured at 22 and 29 months influence lexicon size at 36 and 48 months. Method Children were selected based on parent-reported vocabulary size. We included children with low, medium, and high vocabulary scores. The children's lexicons were coded in terms of phonetic complexity, word length, ND, and WF, and their phonological production skills were based on measures of percent consonants correct and phonetic inventory size extracted from spontaneous speech samples at 29, 36, and 48 months. In the case of ND and WF, we focused on one- and two-syllable nouns. Results Across the age range, the most important factor that explained variance in lexicon size was the WF of nouns. Children who selected low-frequency nouns had larger vocabularies across all ages (22-48 months). The WF of two-syllable nouns and phonological production measured at 29 months influenced lexicon size at 36 months, whereas the WF (of one- and two-syllable words) influenced lexicon size at 48 months. Conclusions The findings support the role of WF and phonological production in explaining expressive vocabulary development. Children enlarge their vocabularies by adding nouns of increasingly lower frequency. Phonological production plays a role in accounting for vocabulary size up until the age of 36 months. Supplemental Material https://doi.org/10.23641/asha.12291074.

Code-switching in young bilingual toddlers: A longitudinal, cross-language investigation.

Although there is a body of work investigating code-switching (alternation between two languages in production) in the preschool period, it largely relies on case studies or very small samples. The current work seeks to extend extant research by exploring the development of code-switching longitudinally from 31 to 39 months of age in two distinct groups of bilingual children: Spanish-English children in San Diego and French-English children in Montréal. In two studies, consistent with previous research, children code-switched more often between than within utterances and code-switched more content than function words. Additionally, children code-switched more from Spanish or French to English than the reverse. Importantly, the factors driving the rate of code-switching differed across samples such that exposure was the most important predictor of code-switching in Spanish-English children whereas proficiency was the more important predictor in French-English children.

Are there Cognitive Benefits of Code-switching in Bilingual Children? A longitudinal study.

The current study explored bilingual parent and child code-switching patterns over time. Concurrent and predictive models of code-switching behaviour on executive function outcomes were also examined in a sample of 29 French-English bilinguals at 36 (Wave 1) and 61 (Wave 2) months of age. We investigated whether code-switching typology in a single-language context predicted executive function performance at each wave independently, and whether growth in code-switching frequency across waves predicted executive function performance at Wave 2. At both waves, parents and children participated in two free play sessions (in English and French), followed by a battery of executive function tasks administered in the dominant language. Results indicate more frequent code-switching from the non-dominant to the dominant language in children, and that children code-switch to fill lexical gaps. Results also suggest that less frequent code-switching in a single-language context is associated with better inhibitory control skills during the preschool period.