How early do children produce multiword utterances? Do children's early utterances reflect abstract syntactic knowledge or are they the result of data-driven learning? We examine this issue through corpus analysis, computational modeling, and adult simulation experiments. Chapter 1 investigates when children start producing multiword utterances;…

We trained a computational model (the Chunk-Based Learner; CBL) on a longitudinal corpus of child-caregiver interactions in English to test whether one proposed statistical learning mechanism--backward transitional probability--is able to predict children's speech productions with stable accuracy throughout the first few years of development. We…

Understanding how a child's language system develops into an adult-like system is a central question in language development research. An increasingly influential account proposes that the brain constantly generates top-down predictions and matches them against incoming input, with higher-level cognitive models serving to minimize prediction…

Evidence shows individual variation in lexical acquisition as a function of socioeconomic status and linguistic input. Research has primarily involved English-speaking populations and considered only mothers' child-directed speech. This study analyzes the effects of socioeconomic status on quantitative and qualitative properties of linguistic…

For many people, learning a second language as an adult is a challenging endeavor. Much interest in the study of adult second language learning has concerned the type of input that learners receive in their second language, with findings suggesting that second language learners are often exposed to a register of speech called 'foreigner talk' that…

Linguistic input in multi-lingual/-cultural contexts is highly variable. We examined the production of English and Malay laterals by fourteen early bilingual preschoolers in Singapore who were exposed to several allophones of coda laterals: Malay caregivers use predominantly clear-l in English and Malay, but their English coda laterals can also be…

Language learners need to map a continuous, multidimensional acoustic signal to discrete abstract speech categories. The complexity of this mapping poses a difficult learning problem, particularly for second language learners who struggle to acquire the speech sounds of a non-native language, and almost never reach native-like ability. A common…

Parent language input is a well-established predictor of child language development. Multisensory attention skills (MASks; intersensory matching, shifting and sustaining attention to audiovisual speech) are also known to be foundations for language development. However, due to a lack of appropriate measures, individual differences in these skills…

Age of acquisition (AoA) is a measure of word complexity which refers to the age at which a word is typically learned. AoA measures have shown strong correlations with reading comprehension, lexical decision times, and writing quality. AoA scores based on both adult and child data have limitations that allow for error in measurement, and increase…

Across languages, lexical items specific to infant-directed speech (i.e., 'baby-talk words') are characterized by a preponderance of onomatopoeia (or highly iconic words), diminutives, and reduplication. These lexical characteristics may help infants discover the referential nature of words, identify word referents, and segment fluent speech into…

The words in children's language learning environments are strongly predictive of cognitive development and school achievement. But how do we measure language environments and do so at the scale of the many words that children hear day in, day out? The quantity and quality of words in a child's input are typically measured in terms of total amount…

High rates of error and variability in early word production may signal speech sound disorder. However, there is little consensus regarding the degree of error and variability that may be expected in the typical range. Relatedly, while variables including child age, word frequency and word phonological neighbourhood density are associated with…

Purpose: The language that children hear early in life is associated with their speech-language outcomes. This line of research relies on naturalistic observations of children's language input, often captured with daylong audio recordings. However, the large quantity of data that daylong recordings generate requires novel analytical tools to…

To explore the potential contribution of parents' causal talk to preschooler's emerging scientific literacy and related interests, we observed 153 parent-child dyads playing together in a museum and in the lab. As in previous work, the frequency with which parents referenced causal information in their speech predicted the strength of their…

To evaluate which features of spoken language aid infant word learning, a corpus of infant-directed speech (M. R. Brent & J. M. Siskind, 2001) was characterized on several linguistic dimensions and statistically related to the infants' vocabulary outcomes word by word. Comprehension (at 12 and 15 months) and production (15 months) were…