Language mixing is a common feature of many bilingually-raised children's input. Yet how it is related to their language development remains an open question. The current study investigated mixed-language input indexed by observed (30-second segment) counts and proportions in day-long recordings as well as parent-reported scores, in relation to infant vocal activeness (i.e., volubility) when infants were 10 and 18 months old. Results suggested infants who received a higher score or proportion of mixed input in one-on-one social contexts were less voluble. However, within contexts involving language mixing, infants who heard more words were also the ones who produced more vocalizations. These divergent associations between mixed input and infant vocal development point for a need to better understand the causal factors that drive these associations.

The hairdresser who carries Ovid's invitation to his puella in Amores 1.11 is almost immediately blamed for his rejection in 1.12, before that blame is transferred to the tablets carrying that invitation. Nape (the enslaved hairdresser of the puella) has been linked to the character Dipsas, appearing in 1.7, specifically through the descriptor sobria. By focussing on the use of the verb uerto, the reference to the mythical strix, and curses related to the old age of both Dipsas and the tablets in 1.7 and 1.12, this note demonstrates that the supernatural word choice further connects Nape with Dipsas.

While socioeconomic disparities in the home language environment have been well established, the mechanisms explaining these disparities are poorly understood. One plausible mechanism is heightened stress. The current study investigated whether maternal perceived stress was 1) associated with measures of the home language environment, and 2) mediated the relation between socioeconomic disparities and the home language environment. Data from three independent studies were analyzed, which together comprised 322 mother-child dyads. Two studies included mothers and their six- to twelve-month-old infants (N = 227). The third included mothers and their five- to nine-year-old children (N = 95). Mothers reported their educational attainment, income, and stress. Language Environment Analysis (LENA) measured the home language environment. As has been previously reported, socioeconomic disparities were observed in adult words and conversational turns. Stress did not mediate these associations, nor was it associated with adult words or conversational turns. Alternate mechanisms for future exploration are discussed.

Parental input is considered a key predictor of language achievement during the first years of life, yet relatively few studies have assessed its effects on longer-term outcomes. We assess the effects of parental quantity of speech, use of parentese (the acoustically exaggerated, clear, and higher-pitched speech), and turn-taking in infancy, on child language at 5 years. Using a longitudinal dataset of daylong LENA recordings collected with the same group of English-speaking infants (N=44) at 6, 10, 14, 18, 24 months and then again at 5 years, we demonstrate that parents’ consistent (defined as stable and high) use of parentese in infancy was a potent predictor of lexical diversity, mean length of utterance, and frequency of conversational turn-taking between children and adults at Kindergarten entry. Together, these findings highlight the potential importance of a high-quality language learning environment in infancy for success at the start of formal schooling.

Using a meta-analytic approach, we evaluate the association between socioeconomic status (SES) and children's experiences measured with the Language Environment Analysis (LENA) system. Our final analysis included 22 independent samples, representing data from 1583 children. A model controlling for LENATM measures, age and publication type revealed an effect size of rz= .186, indicating a small effect of SES on children's language experiences. The type of LENA metric measured emerged as a significant moderator, indicating stronger effects for adult word counts than child vocalization counts. These results provide important evidence for the strength of association between SES and children's everyday language experiences as measured with an unobtrusive recording analyzed automatically in a standardized fashion.

Code-switching is a common phenomenon in bilingual communities, but little is known about bilingual parents’ code-switching when speaking to their infants. In a pre-registered study, we identified instances of code-switching in day-long at-home audio recordings of 21 French–English bilingual families in Montreal, Canada, who provided recordings when their infant was 10 and 18 months old. Overall, rates of infant-directed code-switching were low, averaging 7 times per hour (6 times per 1,000 words) at 10 months and increasing to 28 times per hour (18 times per 1,000 words) at 18 months. Parents code-switched more between sentences than within a sentence; this pattern was even more pronounced when infants were 18 months than when they were 10 months. The most common apparent reasons for code-switching were to bolster their infant's understanding and to teach vocabulary words. Combined, these results suggest that bilingual parents code-switch in ways that support successful bilingual language acquisition.

Parents play an important role in creating home language environments that promote language development. A nonequivalent group design was used to evaluate the effectiveness of a community-based implementation of LENA Start™, a parent-training program aimed at increasing the quantity of adult words (AWC) and conversational turns (CT). Parent-child dyads participated in LENA Start™ (n = 39) or a generic parent education program (n = 17). Overall, attendance and engagement in the LENA StartTM program were high: 72% of participants met criteria to graduate from the program. Within-subject gains were positive for LENA Start™ families. Comparison families declined on these measures. However, both effects were non-significant. Between-group analyses revealed small to medium-sized effects favoring LENA Start™ and these were significant for child vocalizations (CV) and CT but not AWC. These results provide preliminary evidence that programs like LENA StartTM can be embedded in community-based settings to promote quality parent-child language interactions.

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 behaviors, and in early neurodevelopment, might underlie SES-based differences in language that emerge later on. Analysis of natural language samples from a predominantly low-/mid-income sample of mother-infant dyads, obtained using the Language Environment Analysis (LENA) system, found that maternal reports of exposure to stressful life events, and perceived stress, were negatively correlated with child vocalizations and conversational turns when infants were 6 and 12 months of age. Greater numbers of vocalizations and conversational turns were also associated with lower relative theta power and higher relative gamma power in 6- and 12-month baseline EEG – a pattern that might support subsequent language development.

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 using the LENA system. We compared a typical day, with spontaneous occurring activities, with an instructed day when caregivers were prompted to do book reading and toy play. Book sharing resulted in a combination of more parent talk, child talk, and interactions than other language activities. Research context did not influence outcomes: no differences were found in language use between the spontaneous and the instructed activities. Overall it seems clear that even with infants shared reading is a strong unique stimulator of language use from parent and child.