There is considerable controversy over the factors that shape infants' developing knowledge of grammar. Work with artificial languages suggests that infants' ability to track statistical regularities within the speech they hear could, in principle, support grammatical development. However, little work has tested whether infants' performance on…

Children's early vocabulary shows sex differences -- with boys having smaller vocabularies than age-comparable girls -- a pattern that becomes evident in both singletons and twins. Twins also use fewer words than their singleton peers. However, we know relatively less about sex differences in early gesturing in singletons or twins, and also how…

Fourteen-month-old infants are unable to link minimal pair nonsense words with novel objects (Stager & Werker, 1997). Might an adult's productions in a word learning context support minimal pair word-object association in these infants? We recorded a mother interacting with her 24-month-old son, and with her 5-month-old son, producing nonsense…

Research on sources of individual difference in parental Infant-Directed Speech (IDS) is limited and there is a particular lack of research on fathers' compared to mothers' speech. This study examined the predictive relations between infant characteristics and variability in paternal lexical diversity (LD) in dyadic free play with two-year-olds (M…

We examined the functions of mothers' speech to infants during two tasks -- book-sharing and bead-stringing -- in low-income, ethnically diverse families. Mexican, Dominican, and African American mothers and their infants were video-recorded sharing wordless books and toy beads in the home when infants were aged 1;2 and 2;0. Mothers' utterances…

This study examined the roles of parental gender and context in the communicative functions of parents' child-directed speech. Seventy three families with toddlers participated in the study. Dyadic and triadic parent-toddler interactions were videotaped during structured play activities. Results indicated context-dependent variability in parents'…

Pierce "et al." (2017) have proposed that variations in the timing, quality and quantity of language input during the earliest stages of development are related to variations in the development of phonological working memory and, in turn, to later language learning outcomes. To examine this hypothesis, three groups of children who are…

This study explores whether children can learn a structural processing bias relevant to pronoun interpretation from brief training. Over three days, 42 five-year-olds were exposed to narratives exhibiting a first-mentioned tendency. Two characters were introduced, and the first-mentioned was later described engaging in a solo activity. In our…

Studies on the relationship between bookreading and language development typically lack data about which books are actually read to children. This paper reports on an Internet survey designed to address this data gap. The resulting dataset (the Infant Bookreading Database or IBDb) includes responses from 1,107 caregivers of children aged 0-36…

This article presents data on lexical development of 881 Israeli Hebrew-speaking monolingual toddlers ages 1;0 to 2;0. A Web-based version of the Hebrew MacArthur-Bates Communicative Development Inventories (H-MB-CDI) was used for data collection. Growth curves for expressive vocabulary, receptive vocabulary, actions and gestures were…

The goals of this study were to analyze the growth and stability of vocabulary, mean length of the three longest utterances (MLLUw), and sentence complexity in European Portuguese-speaking children aged 1;4-2;6, to explore differences in growth as a function of personal and family-related variables, and to investigate the inter-relationships among…

This study compares the use of the variable (q), which is realized as rural [q] and urban [?], in the speech of twenty-two parents and their twenty-one children from the village of Oyoun Al-Wadi in Syria. The study shows that children acquire the general gendered linguistic pattern of the community but do not replicate the linguistic frequencies…

This study examines the influence of language-internal (frequency and complexity of linguistic properties), language-external (percent French input, socioeconomic status (SES), and gender), and lexical factors (size of total and French vocabulary) on the phonological production abilities of monolingual and bilingual French-speaking children, aged…

This study assessed the status of te reo Maori, the indigenous language of New Zealand, in the context of New Zealand English. From a broadly representative sample of 6327 two-year-olds ("Growing Up in New Zealand"), 6090 mothers (96%) reported their children understood English, and 763 mothers (12%) reported their children understood…

Existing studies have observed a robust relationship between infants' pointing gestures and language outcomes. By contrast, infants' overall vocal production is not related to language outcomes. One possible explanation for the association between pointing and language is that pointing gestures, as compared to vocalizations, may elicit more verbal…