Early vocabulary development benefits from diverse lexical exposures within children's language environment. However, the influence of lexical diversity on children as they enter middle childhood and are exposed to multimodal language inputs remains unclear. This study evaluates global and local aspects of lexical diversity in three…

Blind adults display language-specificity in their packaging and ordering of events in speech. These differences affect the representation of events in "co-speech gesture"--gesturing with speech--but not in "silent gesture"--gesturing without speech. Here we examine when in development blind children begin to show adult-like…

The hypothesis that impoverished language experience affects complex sentence structure development around the end of early childhood was tested using a fully randomized, sentence-to-picture matching study in American Sign Language (ASL). The participants were ASL signers who had impoverished or typical access to language in early childhood. Deaf…

Recent years have seen a flourishing of Natural Language Processing models that can mimic many aspects of human language fluency. These models harness a simple, decades-old idea: It is possible to learn a lot about word meanings just from exposure to language, because words similar in meaning are used in language in similar ways. The successes of…

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…

Two word-learning experiments were conducted to investigate the understanding of negative sentences in 18- and 24-month-old children. In Experiment 1, after learning that "bamoule" means "penguin" and "pirdaling" means "cartwheeling," 18-month-olds (n = 48) increased their looking times when listening to…

When children acquire language, they often learn words in the absence of direct instruction (e.g. "This is a ball!") or even social cues to reference (e.g. eye gaze, pointing). However, there are few accounts of how children do this, especially in cases where the referent of a new word is ambiguous. Across two experiments, we test…

Iconicity--the correspondence between form and meaning--may help young children learn to use new words. Early-learned words are higher in iconicity than later learned words. However, it remains unclear what role iconicity may play in actual language use. Here, we ask whether iconicity relates not just to the age at which words are acquired, but…

Literacy is a powerful tool against poverty, leading to further education and vocational success. In sub-Saharan Africa, schoolchildren commonly learn in two languages--African and European. Multiple early literacy skills (including phonological awareness and receptive language) support literacy acquisition, but this has yet to be empirically…

The question of a sensitive period in language acquisition has been subject to extensive research and debate for more than half a century. While it has been well established that the ability to learn new languages declines in early years, the extent to which this outcome depends on biological maturation in contrast to previously acquired knowledge…