Disentangling genetic and environmental influences on early language development: The interplay of genetic propensity for negative emotionality and surgency, and parenting behavior effects on early language skills in an adoption study.

Parenting and children's temperament are important influences on language development. However, temperament may reflect prior parenting, and parenting effects may reflect genes common to parents and children. In 561 U.S. adoptees (57% male) and their birth and rearing parents (70% and 92% White, 13% and 4% African American, and 7% and 2% Latinx, respectively), this study demonstrated how genetic propensity for temperament affects language development, and how this relates to parenting. Genetic propensity for negative emotionality inversely predicted language at 27 months (ß = -.15) and evoked greater maternal warmth (ß = .12), whereas propensity for surgency positively predicted language at 4.5 years (ß = .20), especially when warmth was low. Parental warmth (ß = .15) and sensitivity (ß = .19) further contributed to language development, controlling for common gene effects.

Receptive and expressive language ability differentially support symbolic understanding over time: Picture comprehension in late talking and typically developing children.

Symbols are a hallmark of human communication, and a key question is how children's emerging language skills relate to their ability to comprehend symbols. In particular, receptive and expressive vocabulary may have related, but distinct, roles across early development. In a longitudinal study of late talking (LT) and typically developing (TD) children, we differentiated the extent to which expressive and receptive language skills predicted symbolic understanding as reflected in picture comprehension and how language skills inter-related with social skills. LT and TD children were tested on a picture comprehension task that manipulated the availability of verbal labels at 2.0-2.4 years and 3.5-3.9 years of age. Although all children improved in accuracy over time as expected, TD children exhibited an advantage over LT children, despite both groups using verbal labels to inform their mapping of picture-object relationships. Receptive and expressive vocabulary also differed in their contribution at different ages; receptive vocabulary predicted performance at ∼2.0 years of age, and expressive vocabulary predicted performance at ∼3.5 years of age. Task performance at 3.5 years was predicted by earlier receptive vocabulary, but this effect was largely mediated by concurrent expressive vocabulary. Social ability across the whole sample at ∼2.0 years also predicted and mediated the effect of receptive vocabulary on concurrent task performance. These findings suggest that LT children may have delays in developing picture comprehension over time and also that social ability and language skills may differentially relate to symbolic understanding at key moments across development.

Caregivers use gesture contingently to support word learning.

Children learn words in environments where there is considerable variability, both in terms of the number of possible referents for novel words, and the availability of cues to support word-referent mappings. How caregivers adapt their gestural cues to referential uncertainty has not yet been explored. We tested a computational model of cross-situational word learning that examined the value of a variable gesture cue during training across conditions of varying referential uncertainty. We found that gesture had a greater benefit for referential uncertainty, but unexpectedly also found that learning was best when there was variability in both the environment (number of referents) and gestural cue use. We demonstrated that these results are reflected behaviourally in an experimental word-learning study involving children aged 18-24-month-olds and their caregivers. Under similar conditions to the computational model, caregivers not only used gesture more when there were more potential referents for novel words, but children also learned best when there was some referential ambiguity for words. Thus, caregivers are sensitive to referential uncertainty in the environment and adapt their gestures accordingly, and children are able to respond to environmental variability to learn more robustly. These results imply that training under variable circumstances may actually benefit learning, rather than hinder it.

Risk factors for early language delay in children within a minority ethnic, bilingual, deprived environment (Born in Bradford's Better Start): a UK community birth cohort study.

BACKGROUND: Preschool language skills and language delay predict academic and socioemotional outcomes. Children from deprived environments are at a higher risk of language delay, and both minority ethnic and bilingual children can experience a gap in language skills at school entry. However, research that examines late talking (preschool language delay) in an ethnically diverse, bilingual, deprived environment at age 2 is scarce. METHODS: Data from Born in Bradford's Better Start birth cohort were used to identify rates of late talking (≤10th percentile on the Oxford-Communicative Development Inventory: Short) in 2-year-old children within an ethnically diverse, predominantly bilingual, deprived UK region (N=712). The relations between known demographic, maternal, distal and proximal child risk factors, and language skills and language delay were tested using hierarchical linear and logistic regression. RESULTS: A total of 24.86% of children were classified as late talkers. Maternal demographic factors (ethnicity, born in UK, education, financial security, employment, household size, age) predicted 3.12% of the variance in children's expressive vocabulary. Adding maternal language factors (maternal native language, home languages) and perinatal factors (birth weight, gestation) to the model predicted 3.76% of the variance. Adding distal child factors (child sex, child age) predicted 11.06%, and adding proximal child factors (receptive vocabulary, hearing concerns) predicted 49.51%. Significant risk factors for late talking were male sex (OR 2.07, 95% CI 1.38 to 3.09), receptive vocabulary delay (OR 8.40, 95% CI 4.99 to 14.11) and parent-reported hearing concerns (OR 7.85, 95% CI 1.90 to 32.47). Protective factors were increased household size (OR 0.85, 95% CI 0.77 to 0.95) and age (OR 0.82, 95% CI 0.70 to 0.96). CONCLUSIONS: Almost one in four children living in an ethnically diverse and deprived UK area have early language delay. Demographic factors explained little variance in early vocabulary, whereas proximal child factors held more predictive value. The results indicate further research on early language delay is warranted for vulnerable groups.

A randomised controlled feasibility trial of an early years language development intervention: results of the 'outcomes of Talking Together evaluation and results' (oTTer) project.

BACKGROUND: Early language difficulties are associated with poor school readiness and can impact lifelong attainment. The quality of the early home language environment is linked to language outcomes. However, few home-based language interventions have sufficient evidence of effectiveness in improving preschool children's language abilities. This study reports the first stage in the evaluation of a theory-based programme, Talking Together (developed and delivered by BHT Early Education and Training) given over 6 weeks to families in the home setting. We aimed to test the feasibility and acceptability of delivering Talking Together in the Better Start Bradford community prior to a definitive trial, using a two-armed randomised controlled feasibility study. METHODS: Families from a single site within the Better Start Bradford reach area were randomly allocated (1:1) to the Talking Together intervention or a wait list control group. Child language and parent-level outcome measures were administered before randomisation (baseline), pre-intervention (pre-test), 2 months post-intervention start (post-test), and 6 months post-intervention start (follow-up). Routine monitoring data from families and practitioners were also collected for eligibility, consent, protocol adherence, and attrition rates. Descriptive statistics on the feasibility and reliability of potential outcome measures were analysed alongside qualitative feedback on trial design acceptability. Pre-defined progression-to-trial criteria using a traffic light system were assessed using routine monitoring data. RESULTS: Two-hundred and twenty-two families were assessed for eligibility; of these, 164 were eligible. A total of 102 families consented and were randomised (intervention: 52, waitlist control: 50); 68% of families completed outcome measures at 6-month follow-up. Recruitment (eligibility and consent) reached 'green' progression criteria; however, adherence reached 'amber' and attrition reached 'red' criteria. Child- and parent-level data were successfully measured, and the Oxford-CDI was identified as a suitable primary outcome measure for a definitive trial. Qualitative data not only indicated that the procedures were largely acceptable to practitioners and families but also identified areas for improvement in adherence and attrition rates. CONCLUSIONS: Referral rates indicate that Talking Together is a much-needed service and was positively received by the community. A full trial is feasible with adaptations to improve adherence and reduce attrition. TRIAL REGISTRATION: ISRCTN registry ISRCTN13251954. Retrospectively registered 21 February 2019.

Multiple Mechanisms of Word Learning in Late-Talking Children: A Longitudinal Study.

PURPOSE: The aim of this study was to identify variability in word-learning mechanisms used by late-talking children using a longitudinal study design, which may explain variability in late-talking children's outcomes. METHOD: A cohort of typically developing children (n = 40) and children who were classified as late-talking children at age 2;0 (years;months; ≤ 10th percentile on expressive vocabulary, n = 21) were followed up at ages 3;0 and 3;6. We tested the cohort across tasks designed to isolate different mechanisms involved in word learning: encoding and producing spoken forms of words (using a nonword repetition task), identifying referents for words (using a fast mapping task), and learning associations between words and referents (using a cross-situational word-learning task). RESULTS: Late-talking children had lower accuracy on nonword repetition than typically developing children, despite most of the sample reaching typical ranges for expressive vocabulary at age 3;6. There were no between-groups differences in fast mapping and retention accuracy; however, both were predicted by concurrent expressive vocabulary. Late-talking children performed less accurately than typically developing children on cross-situational word-learning retention trials, despite showing no between-groups differences during training trials. Combining performance across all three tasks predicted approximately 45% of the variance in vocabulary outcomes at the last time point. CONCLUSIONS: Late-talking children continue to have deficits in phonological representation that impact their word-learning ability and expressive language abilities but do not show difficulties in fast mapping novel words. Late-talking children may also struggle to retain associative information about word-referent mappings. Late-talking children thus use some, but not all, word-learning mechanisms differently than typically developing children. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.20405856.