The disparity in the amount and quality of language that low-income children hear relative to their more-affluent peers is often referred to as the 30-million-word gap. Here, we expand the literature about this disparity by reporting the relative contributions of the quality of early parent-child communication and the quantity of language input in 60 low-income families. Including both successful and struggling language learners from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, we noted wide variation in the quality of nonverbal and verbal interactions (symbol-infused joint engagement, routines and rituals, fluent and connected communication) at 24 months, which accounted for 27% of the variance in expressive language 1 year later. These indicators of quality were considerably more potent predictors of later language ability than was the quantity of mothers' words during the interaction or sensitive parenting. Bridging the word gap requires attention to how caregivers and children establish a communication foundation within low-income families.

This study provides an expanded view of joint attention and its relation to expressive language development. A total of 144 toddlers (40 typically developing, 58 with autism spectrum disorder [ASD], 46 with developmental delay [DD]) participated at 24 and 31 months. Toddlers who screened positive for ASD risk, especially those subsequently diagnosed with ASD, had poorer joint attention skills, joint engagement during parent-toddler interaction, and expressive language. Findings highlight the dynamic relation between joint attention and language development. In the ASD and DD groups, joint engagement predicted later expressive vocabulary, significantly more than predictions based on joint attention skills. Joint engagement was most severely impacted when toddlers did not talk initially and improved markedly if they subsequently began to speak.

The cultural value of respeto (respect) is central to Latine parenting. Yet, how respeto manifests in the interactions of Latine parents and their young children remains unexamined. Low‐income Mexican immigrant Spanish‐speaking mothers and their 2.5‐year‐old toddlers (N = 128) were video‐recorded during play (Mage = 30.2 months, SD = 0.52), and two culturally informed items of respeto were coded: parent calm authority and child affiliative obedience. Respeto related to standard ratings of mother and child interactions (e.g., maternal sensitivity and child engagement) but also captured unique features of parent–child interactions. Respeto related to mothers' and toddlers' language production and discourse during the interaction, and explained unique variance in language variables above standard ratings of mother–child interaction. This is the first effort to document a culturally salient aspect of dyadic interaction in Mexican immigrant mothers and young children and to show that respeto relates to language use during mother–child interactions.

Parents of children with ASD (N = 86; mean age 44.8 months; 67 boys) were randomized to either WHO Caregiver Skills Training (CST) delivered in public health settings in Italy or enhanced treatment-as-usual. Primary blinded outcomes were 3-months post-intervention change scores of autism severity and engagement during caregiver-child interaction. CST was highly acceptable to caregivers and feasibly delivered by trained local clinicians. Intention-to-treat analysis showed a large and significant effect on parent skills supporting joint engagement and a smaller significant effect on flow of interaction. Expected changes in child autism severity and joint engagement did not meet statistical significance. Analysis of secondary outcomes showed a significant effect on parenting stress, self-efficacy, and child gestures. Strategies to improve the effectiveness of CST are discussed.

Joint engagement—the sharing of events during social interactions—is an important context for early learning. To date, sharing topics that are only heard has not been systematically documented. To describe the development of auditory joint engagement, 48 child–parent dyads were observed 5 times from 12 to 30 months during seminaturalistic play. Reactions to 4 types of sounds—overheard speech about the child, instrumental music, animal calls, and mechanical noises—were observed before and as parents scaffolded shared listening and after the sound ceased. Before parents reacted, even 12-month-old infants readily alerted and oriented to the sounds; over time they increasingly tried to share new sounds with their parents. When parents then joined in sharing a sound, periods of auditory joint engagement often ensued, increasing from two thirds of 12-month observations to almost ceiling level at the 18- through 30-month observations. Overall, the developmental course and structure of auditory joint engagement and joint engagement with multimodal objects and events are remarkably similar. Symbol-infused auditory joint engagement occurred rarely at first but increased steadily. Children’s labeling of the sound and parents’ language scaffolding also increased linearly while child pointing toward it rose until 18 months and then declined. Future studies should address variations in the development of auditory joint engagement, whether autism spectrum disorder affects how toddlers share sounds, and the role auditory joint engagement may play in gestural and language development.