Vocabulary checklists completed by caregivers are a common way of measuring children's vocabulary knowledge. We provide evidence from checklist data from 31 children with and without autism spectrum disorder. When asked to report twice about whether or not their child produces a particular word, caregivers are largely consistent in their…

While semantic and syntactic properties of verb meaning can impact the success of verb learning at a single age, developmental changes in how these factors influence acquisition are largely unexplored. We ask whether the impact of syntactic and semantic properties on verb vocabulary development varies with age and language ability for toddlers…

Perception verbs and mental verbs have significant overlap in their syntax and semantics; both reference mental representations when taking embedded clauses, as in "I see that Maria was here" and "I think that Maria was here." Some have suggested that perception is more accessible for young children than mental states, raising…

We assessed 24-month-old infants' lexical processing efficiency for both novel and familiar words. Prior work documented that 19-month-olds successfully identify referents of familiar words (e.g., The dog is so little) as well as novel words whose meanings were informed only by the surrounding sentence (e.g., The vep is crying), but that the speed…

Across a diverse range of languages, children proceed through similar stages in their production of causal language: their initial verbs lack internal causal structure, followed by a period during which they produce causative overgeneralizations, indicating knowledge of a productive causative rule. We asked in this study whether a child not…

The present study investigates English-learning infants' early understanding of the link between the grammatical category "verb" and the conceptual category "event," and their ability to recruit morphosyntactic information online to learn novel verb meanings. We report two experiments using an infant-controlled…

The study investigated the influence of universal and language-specific morpho-syntactic properties (i.e., flexible word order, case) on the acquisition of verb argument structures in German compared with English. To this end, 65 three- to nine-year-old German learning children and adults were asked to act out grammatical ("The sheep…

Evidentiality in language marks how information contained in a sentence was acquired. For instance, Turkish has two past-tense morphemes that mark whether access to information was direct (typically, perception) or indirect (hearsay/inference). Full acquisition of evidential systems appears to be a late achievement cross-linguistically. Currently,…

Handshape works differently in nouns versus a class of verbs in American Sign Language (ASL) and thus can serve as a cue to distinguish between these two word classes. Handshapes representing characteristics of the object itself ("object" handshapes) and handshapes representing how the object is handled ("handling" handshapes)…