A prominent hypothesis holds that by speaking to infants in infant-directed speech (IDS) as opposed to adult-directed speech (ADS), parents help them learn phonetic categories. Specifically, two characteristics of IDS have been claimed to facilitate learning: "hyperarticulation," which makes the categories more "separable," and…

Many Western industrialized nations have high levels of ethnic diversity but to date there are very few studies which investigate prelinguistic and early language development in infants from ethnic minority backgrounds. This study tracked the development of infant communicative gestures from 10 to 12 months (n = 59) in three culturally distinct…

Do parents fine-tune the MLU of utterances with a particular word as the word is on the verge of appearing in the child's production? We analyzed a corpus of spontaneous interactions of 30 dyads. The children were in the initial stages of their lexical development, and the parents' utterances containing the words the children eventually acquired…

Objective: The tendency to vocalize toward objects is ubiquitous among young infants. However, little is known about the range of this tendency and its contribution to language development. Therefore, this longitudinal study objective was to explore the role of three forms of vocal behavior (vocalization, babbling, and speech) directed toward…

Bilingual infants must navigate the similarities and differences between their languages to achieve native proficiency in childhood. Bilinguals learning to find individual words in fluent speech face the possibility of conflicting cues to word boundaries across their languages. Despite this challenge, bilingual infants typically begin to segment…

Researchers agree that early literacy activities, like book sharing and parent-child play, are important for stimulating language development. We hypothesize that book sharing is most powerful because it elicits more interactive talk in young children than other activities. Parents of 43 infants (9-18 months) made two daylong audio recordings…

Our aim was to assess whether infants influence the quantity and quality of their mothers' speech to them and, in turn, whether this maternal speech influences children's later language. As 189 mothers interacted with each of their twins at age 0;5, we calculated the number of utterances, the proportion of sensitive utterances, and the proportion…

We investigated online early comprehension in Italian children aged 12 and 20 months, focusing on the role of morphosyntactic features (i.e., gender) carried by determiners in facilitating comprehension and anticipating upcoming words. A naturalistic eye-tracking procedure was employed, recording looking behaviours during a classical…

The influence of motor knowledge on speech perception is well established, but the functional role of the motor system is still poorly understood. The present study explores the hypothesis that speech production abilities may help infants discover phonetic categories in the speech stream, in spite of coarticulation effects. To this aim, we…

Infants begin to understand some of the meanings of the adjective "good" at around thirteen months, but it is not clear when they start to map it to concepts in the moral domain. We investigated infants' and toddlers' knowledge of "good" in the domains of help and fairness. Participants at 20 and 30 months were shown computer…

Purpose: Fathers play a critical but underresearched role in their children's cognitive and linguistic development. Focusing on two-parent families with a mother and a father, the present longitudinal study explores the amount of paternal input infants hear during the first 2 years of life, how this input changes over time, and how it relates to…

Associations have been observed between socioeconomic status (SES) and language outcomes from early childhood, but individual variability is high. Exposure to high levels of stress, often associated with low-SES status, might influence how parents and infants interact within the early language environment. Differences in these early language…

The transaction of children's core language skill and their home learning environment was assessed across 5 waves from infancy (15 months) up to adolescence (11 years) in 1,751 low-socioeconomic status families. Child core language skill and the quality of the home learning environment were each stable across waves, and the two covaried at each…

The purpose of the current study was to examine effects of bilingual language input on infant word segmentation and on talker generalization. In the present study, monolingually and bilingually exposed infants were compared on their abilities to recognize familiarized words in speech and to maintain generalizable representations of familiarized…

What is the function of babbling in language learning? We examined the structure of parental speech as a function of contingency on infants' non-cry prelinguistic vocalizations. We analyzed several acoustic and linguistic measures of caregivers' speech. Contingent speech was less lexically diverse and shorter in utterance length than…