Human languages, signed and spoken, can be characterized by the structural patterns they use to associate communicative "forms" with "meanings." One such pattern is paradigmatic morphology, where complex words are built from the systematic use "and re-use" of sub-lexical units. Here, we provide evidence of emergent…

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…

English-speaking children use plural morphology from around the age of 2, yet often omit the syllabic plural allomorph /-[schwa]z/ until age 5 (e.g., "bus(es)"). It is not clear if this protracted acquisition is due to articulatory difficulties, low input frequency, or fricative-final words (e.g., "bus," "nose") being…

Research in language development has only recently begun to focus on the inherent variability of language. Previous studies have explored at what age children begin to produce variable linguistic forms and how these forms progress through development. While children produce adult-like variation early on, some variable forms take longer to acquire…

Research consistently shows that adults engaged in tutored acquisition benefit from explicit instruction in several linguistic domains. For preschool children, it is often assumed that such explicit instruction does not make a difference. In the present study, we investigated whether explicit instruction affected young learners in acquiring a…

The Mandarin resultative verb compound (RVC; e.g., "tui dao" "push fall" and "pa shang" "climb ascend") encodes complex events composed of an initiating action and resulting activity or state. This study investigated when Mandarin-speaking children acquired this language-specific device. Specifically, we…

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…

Young English-speaking children often omit auxiliary verbs from their speech, producing utterances such as "baby crying" alongside the more adult-like "baby is crying." Studies have found that children's proficiency with auxiliary BE is correlated with frequency statistics in the input, leading some researchers to argue that…