Based on findings from a variety of research, Shin and Miller (2022) propose a 4-step process that children go through as they learn sociolinguistic variation. Their proposal raises many interesting questions that should inspire future research. Here, I discuss their Step 1 -- the stage in which, according to their proposal, children produce only…

I argue that the variation within and across contexts detailed by Shin & Miller is indicative of a broader phenomenon in which morphosyntax and the discourse context are intertwined, including elements like perspective, discourse relations, information structure, and common ground. Appealing to independent evidence highlighting the role of…

The first stage of combinatorial speech is better described as variable than uniform. Talk of variants obscures two different aspects of language (knowledge and use) and two different aspects of language development -- acquisition of the grammar (competence) and deployment of the grammar in speaking and listening (performance). Null subjects and…

The Child Language Data Exchange System (CHILDES), created by Brain MacWhinney and Catherine Snow in 1984, is one of the earliest Open Science and data sharing initiatives in child language development research, and probably in developmental psychology and the behavioral sciences more generally. It is the cornerstone of TalkBank--a repository of…

Children's differing learning trajectories cross-linguistically have been at the forefront of gender acquisition research, often with conflicting results and conclusions. As a result, the source of children's different learning behaviors in gender acquisition has been unclear. I argue that children's gender acquisition is driven by the search for…

A grandmother attempts to teach her four-year-old granddaughter the multiplication tables using simple repetition, but they repeatedly start over at 'three fives'; the child keeps coming up with 'thirty-five'. We consider three possible explanations: self-perpetuating frequency of behavior, saliency of memory and Vygotsky's next or proximal zones…

In English, the sentence "Mary didn't eat pizza or sushi" is assigned the "neither interpretation" (both disjuncts must be false). In Mandarin Chinese, the equivalent sentence is assigned the at least one interpretation (at least one disjunct must be false). The cross-linguistic variation in the interpretation of negative…

A comprehensive theory of child language acquisition requires an evidential base that is representative of the typological diversity present in the world's 7000 or so languages. However, languages are dying at an alarming rate, and the next 50 years represents the last chance we have to document acquisition in many of them. Here, we take stock of…

This dissertation presents a series of case studies concerned with whether the signal in a given set of measurements that we take in the course of linguistic inquiry reflects grammatical competence or performance factors. We know that performance and competence do not always covary, yet it is not uncommon to assume that measurements that we take…

Emerging audio technologies over the last decade have provided a new, unprecedented window into the everyday lives of infants and young children. These new approaches will allow us to begin to address longstanding questions about the nature of language experiences across languages, communities and situations and the role of these experiences in…

This paper provides the first evidence of maternal speech--motherese--in Wichi, an indigenous language with a complex morphology spoken in the Gran Chaco region of Argentina. The corpus consists of 22 hours of video recordings from the daily life of three children, starting from their one-morpheme utterance period (MLU = 1) to the onset of…

This dissertation studies the acquisition of Mandarin relative clauses (RCs), including the distributional pattern of different RC types in adult child-directed speech (study 1) and four-year-old Mandarin-speaking children's comprehension of different RC types (study 2). An RC is a subordinate clause that modifies a noun and is embedded within a…

Scholars of language development have long been challenged to understand the development of functional categories. Traditionally, it was assumed that children's language development initially relies on lexical elements, while functional elements become accessible only at later periods; and that it is lexical growth which bootstraps grammatical…

Previous work suggests that key factors for replicability, a necessary feature for theory building, include statistical power and appropriate research planning. These factors are examined by analyzing a collection of 12 standardized meta-analyses on language development between birth and 5 years. With a median effect size of Cohen's d = 0.45 and…

Language documentation efforts are most often concerned with the adult language and usually do not include the language used by and with children. Essential parts of the natural linguistic behaviour of communities thus remain undocumented, and a growing body of literature explores what language documentation, language maintenance, and language…