When acquiring the English plural, children correctly produce plural words long before they develop an understanding of morphological structure. When acquiring Sesotho noun prefixes, children are aware of the multiple constraints governing variation from a young age. Both of these cases raise questions about the Shin and Miller (2022) account of…

Korean is a classifier language in which bare nouns are not obligatorily number-marked. Children learning other classifier languages like Japanese and Mandarin are late in learning the plural morpheme. In this paper, we present two datasets that suggest that Korean plural marker "-tul" is acquired much earlier, in contrast to what has…

Using a habituation paradigm with a three-switch design, the present study investigated whether 20-month-old French-learning infants use noun and verb morphosyntactic cues to learn novel words in dynamic events differentially when both the agent and the action interpretations are possible. Of particular interest was whether infants' initial…

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…

Languages exhibit variation at all linguistic levels, from phonology, to the lexicon, to syntax. Importantly, that variation tends to be (at least partially) conditioned on some aspect of the social or linguistic context. When variation is unconditioned, language learners regularize it -- removing some or all variants, or conditioning variant use…

Parent input during interaction with young children varies across languages and contexts with regard to the relative number of words from different lexical categories, particularly nouns and verbs. Previous work has focused on spoken language input. Little is known about the lexical composition of parent input in American Sign Language (ASL). We…

Using an oral sentence production task, we investigated how preschoolers (N = 28) produce agreement with complex noun phrases and compared their performance to college students (N = 32) to determine whether preschoolers produce agreement patterns that are qualitatively similar to adults'. We also conducted corpus analyses to investigate relevant…

We investigate bilingual children's perception of assimilations, i.e. phonological rules by which a consonant at a word edge adopts a phonological feature of a neighboring consonant. For instance, English has place assimilation (e.g., "green" is pronounced with a final [m] in "green pen"), while French has voicing assimilation…

The natural numbers may be our simplest, most useful, and best-studied abstract concepts, but their origins are debated. I consider this debate in the context of the proposal, by Gallistel and Gelman, that natural number system is a product of cognitive evolution and the proposal, by Carey, that it is a product of human cultural history. I offer a…

Previous research indicates that infant-directed speech (IDS) is usually slower than adult-directed speech (ADS) and mothers prefer placing a focused word in isolation or utterance-final position in (English) IDS, which may benefit word learning. This study investigated the speaking rate and word position of IDS in two typologically-distinct…

The cross-categorical use of nouns and verbs poses a challenging problem to young language learners because they are known to be less willing to accept that a single form of a word be used for more than one linguistic purpose (e.g., one-form/one-function principle). The present study investigated whether children under 3 years of age are able to…

We present an artificial language experiment investigating (i) how speakers of languages such as English with two-way obligatory distinctions between singular and plural learn a system where singular and plural are only optionally marked, and (ii) how learners extend their knowledge of the plural morpheme when under the scope of negation without…

We report on two experiments that investigated the acquisition of the Tagalog symmetrical voice system, a typologically rare feature of Western Austronesian languages in which there are more than one basic transitive construction and no preference for agents to be syntactic subjects. In the experiments, 3-, 5-, and 7-year-old Tagalog-speaking…

Although children may productively use concrete nouns after limited exposure, complete mastery of adult-like patterns of noun usage can take up to 14 years. We evaluated whether a transition from universal to language-specific naming is part of the refinement in later lexical development, and we compared how this refinement plays out in…

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…