Children with delays in expressive language (late talkers) have heterogeneous developmental trajectories. Some are late bloomers who eventually "catch-up," but others have persisting delays or are later diagnosed with developmental language disorder (DLD). Early in development it is unclear which children will belong to which group. We…

This study investigates the influence of semantic maturation on early lexical development by examining the impact of contextual diversity--known to influence semantic development--on word promotion from receptive to productive vocabularies (i.e., comprehension-expression gap). Study 1 compares the vocabularies of 3685 American-English-speaking…

In typical development, word learning goes from slow and laborious to fast and seemingly effortless. Typically developing 2-year-olds seem to intuit the whole range of things in a category from hearing a single instance named--they have word-learning biases. This is not the case for children with relatively small vocabularies ("late…

Is noun dominance in early lexical acquisition a widespread or a language-specific phenomenon? Thirty Singaporean bilingual English-Mandarin learning toddlers and their mothers were observed in a mother-child play interaction. For both English and Mandarin, toddlers' speech and reported vocabulary contained more nouns than verbs across book…

This mixed two-way experimental, cross-sectional study investigated fast-mapping (FM) of novel nouns and verbs in 63 Persian-speaking toddlers aged 30 months, including 31 late-talking (LT) and 32 typically developing (TD) matched with respect to age and maternal education. Toddlers were classified as LT if they had limited expressive vocabulary…

The purpose of this study was to understand vocabulary characteristics in toddlers who are late talkers (LT) as compared with age-matched (AM) and vocabulary-matched (VM) peers. The semantic categories (e.g., animals, foods, toys) and the percentage of nouns, verbs, and closed-class words in the vocabularies of 36 toddlers (12 LT, 12 AM, 12 VM)…

Young children who hear more child-directed speech (CDS) tend to have larger vocabularies later in childhood, but the specific characteristics of CDS underlying this link are currently underspecified. The present study sought to elucidate how the structure of language input boosts learning by investigating whether repetition of object labels in…

Efficient language use involves the capacity to flexibly adjust to varied pronunciations of words. Although children can contend with some accent variability before their second birthday, it is currently unclear when and how this ability reaches its mature state. In a series of five experiments, we examine the developmental trajectory of toddlers'…

How is number-concept acquisition related to overall language development? Experiments 1 and 2 measured number-word knowledge and general vocabulary in a total of 59 children, ages 30-60 months. A strong correlation was found between number-word knowledge and vocabulary, independent of the child's age, contrary to previous results (D. Ansari et…

Background: Understanding lexical abilities in infants and toddlers is important, yet no single tool can be used. Aims: To perform a validation of a new tool (known as the Picture Naming Game, or "PiNG") for assessing lexical comprehension and production in toddlers and to obtain developmental trends for Italian children. Methods &…

In gender-marking languages, the gender of the noun determines the form of the preceding article. In this study, we examined whether French-learning toddlers use gender-marking information on determiners to recognize words. In a split-screen preferential looking experiment, 25-month-olds were presented with picture pairs that referred to nouns…

Using a preferential looking methodology with novel verbs, Gertner, Fisher and Eisengart (2006 ) found that 21-month-old English children seemed to understand the syntactic marking of transitive word order in an abstract, verb-general way. In the current study we tested whether young German children of this same age have this same understanding.…

In the novel noun generalization task, 2 1/2-year-old children display generalized expectations about how solid and nonsolid things are named, extending names for never-before-encountered solids by shape and for never-before-encountered nonsolids by material. This distinction between solids and nonsolids has been interpreted in terms of an…

Two experiments examined toddlers' noun vocabularies and interpretations of names for solid and non-solid items. Results indicated that one side of the solidity-syntax-category organization mapping was favored. Seventeen- to 33-month olds do not systematically generalize names for solid things by shape similarity until they already know many…