A longitudinal investigation of the role of quantity and quality of child-directed speech in vocabulary development.

“While it is acknowledged that some of this variability is likely due to genetics (see Stromswold, 2001, for a review), environmental factors also play an integral role (see Hoff, 2006, for a review).”

“Children’s early language environments are intimately associated with their trajectories of language development, which in turn predict cognitive and academic development across childhood (Gilkerson et al., 2018; Huttenlocher et al., 2002; Rowe, 2012; Walker et al., 1994).”

“However, the quantity, quality, and diversity of language heard may be different for children from various socioeconomic and cultural backgrounds (Hoff, 2006; Rowe, 2012).”

“Language researchers have been arguing and finding that it is not the quantity but the quality that matters (Rowe, 2012; Wasik & Hindman, in press).”

“For example, the quality of vocabulary input that parents provide to children predicts children’s own vocabulary growth (see Hoff, 2006; Rowe, 2012); encouraging children and parents to talk about mental states predicts children’s theory of mind (Lu, Su, & Wang, 2008; Reese, Sparks, & Leyva, 2010;…”

“Family SES has been repeatedly identified as a highly significant predictor of language development (Hoff, 2003; Huttenlocher et al., 2010; Rowe, 2012).”

“Impor-tantly, these input features have been shown to predict children’s later language abilities [e.g., Hoff & Naigles, 2002; Hurtado, Marchman, & Fernald, 2008; Rowe, 2012].”

“…back to variations in environmental factors, in particular, to family SES (Hoff, 2006) and to the quantity (Huttenlocher et al., 1991) and quality (Cartmill et al., 2013) of parental linguistic input (Hoff, 2003; Hoff and Naigles, 2002; Montag et al., 2015; Rowe, 2012; Weisleder and Fernald, 2013).”

“…complexity, and the frequency of decontextualized language use are all features of good quality input that facilitate the acquisition process, and they tend to be less well represented in parents from lower SES backgrounds (Hoff, 2006; Huttenlocher, Waterfall, Vasilyeva, & Vevea, 2010; Rowe, 2012).”

“More specifically, using data from child–caregiver interactions at 18, 30, and 42 months, Rowe (2012) found that after controlling for input quantity, quality of caregiver input at 18 months, operationalized as lexical diversity (number of different words), lexical sophistication (number of “rare”…”

“Lower level facilitative language techniques, including imitation, labelling, linguistic mapping and directive language, are beneficial rather for children in the prelexical phase, and hinder language development in the lexical phase [98,103].”

“…work of Snow (1972), an extensive body of research has been conducted on the characteristics of speech directed to, or produced in interaction with, young children in the early stages of language acquisition, typically below three years of age (see Hoff, 2006; Rowe, 2012, for reviews of this work).”

“…1991; Huttenlocher, Vasilyeva, Waterfall, Vevea, & Hedges, 2007), and the quantity and quality of mothers’ child-directed speech predicts children’s language growth (Hoff, 2003, 2006; Huttenlocher, Waterfall, Vasilyeva, Vevea, & Hedges, 2010; Rowe, 2012; Song, Spier, & Tamis-Lemonda, 2014).”

“While Rowe (2012) showed that quantity may be important between the first and second birthday, both her and our data show convergent evidence that the diversity of maternal vocabulary and its complexity are most supportive of children’s language and cognitive development after the second birthday.”

“Similarly, Rowe (2012) analyzed the diversity and the sophistication of the parents’ vocabulary and the number of decontextualized utterances during a 90-min parent– child interaction and found links between these parental vocabulary measures and children’s vocabulary knowledge.”

“Linguistic measures of caregivers’ CDS, such as lexical diversity and mean length of utterances, are longitudinal predictors of preschoolers’ oral language development (Hoff-Ginsberg, 1998; Hoff and Naigles, 2002; Huttenlocher et al., 2010; Rowe, 2012; Weisleder and Fernald, 2013).”

“More directive talk may result in caregivers devoting less of their interactions to providing names for objects, descriptions, or elaborations on the activities in which the child and caregiver are engaged (Rowe, 2012).”

“Since then, this finding has been replicated many times, mostly with infants in their second and third year of life [Cartmill et al., 2013; Hirsh-Pasek et al., 2015; Hoff, 2003; Hurtado et al., 2008; Pan et al., 2005; Rowe, 2008, 2012; Weisleder & Fernald, 2013].”

“Decades of research demonstrate significant and strong associations between children’s early language environments and subsequent language and cognitive outcomes (Hart & Risley, 1995; Hoff, 2003; Huttenlocher, Haight, Bryk, Seltzer, & Lyons, 1991; Rowe, 2012; Tamis-LeMonda, Bornstein, Kahana-Kalman, Baumwell, & Cypher…”

“There is evidence showing that parent-child language interaction stimulates language development more than just language input (Gilkerson, Richards, Warren, Oller, Russo & Vohr, 2018; Greenwood, Thiemann-Bourque, Walker, Buzhardt & Gilkerson, 2011; Ramírez-Esparza, García-Sierra & Kuhl, 2014; Rowe, 2012; Warlaumont, R…”

“In the course of the next 24 months, that percentage is more than quadrupled to reach 9% at 42 months (Rowe, 2012).”

“In particular, parent input has been examined, as parents provide an important source of linguistic input during daily interactions with their children in their early language learning environments [Rowe, 2012; Tamis-LeMonda, Bornstein, & Baumwell, 2001].”

“Rowe (2012) validated this perspective in a longitudinal study on vocabulary growth in children aged between 18 and 42 months.”

“Environmental input and experience over time play a crucial role in shaping the trajectory of language acquisition (Rowe, 2012; Weisleder and Fernald, 2013), but the first two years of life signify a particularly rapid period of language development and brain maturation (Pujol et al., 2006) and are…”

“…to predict children’s vocabulary development include the number of different words used, the frequency with which advanced (i.e., infrequently used) vocabulary words are used, and the average length of utterances in child-directed speech (Beals, 1997; Hoff, 2003; Rowe, 2012; Weizman & Snow, 2001).”

“Due to connections between adults’ print exposure, their vocabulary skills, and characteristics of their oral communication (Mol & Bus, 2011; Rowe, 2012; Stanovich et al., 1995), we hypothesize that shared reading in the HLE and the CCLE explains unique variance in vocabulary skills.”

“Address: University of Chicago, Psychology Department, 5848 S. University Ave, Chicago, IL 60637, United States.”

“Note that children vary widely in the quality and diversity of vocabulary they hear (e.g., Rowe, 2012), and so it is not straightforward to determine a representative pre-literacy exposure for children.”

“…1995; Hoff, 2003; Hoff & Naigles, 2003; Huttenlocher, Haight, Bryk, Seltzer, & Lyons, 1991; Huttenlocher, Waterfall, Vasilyeva, Vevea, & Hedges, 2010; Huttenlocher et al., 2007; Naigles & Hoff-Ginsberg, 1998; Newport et al., 1977; Pan et al., 2005; Rowe, 2008, 2012; Weisleder & Fernald, 2013).”

“Granted that children vary in the quantity of speech that they are exposed to by their caregivers (48) in the extent to which that speech is directive rather than discursive (49), is tightly focused on the immediate situation or includes an exploration of situations and events displaced from the here and now (50), and…”

“For example, it has been shown that the quality and quantity of child-directed speech are highly correlated with vocabulary gain in toddlers (Huttenlocher et al. 1991; Rowe 2012).”

“More recently, Rowe (2012) reported that the diversity of vocabulary input toddlers receive at 18 months is related to children’s later vocabulary ability at 42 months even when controlling for SES, amount of input, and children’s vocabulary skill at 18 months.”

“…to children, the diversity of vocabulary, and syntactic complexity of caregiver speech predict child outcomes such as vocabulary size (Cartmill, Armstrong, Gleitman, Goldin-Meadow, Medina & Trueswell, 2013; Hart & Risley, 1995; Huttenlocher, Haight, Bryk, Seltzer & Lyons, 1991; Rowe, 2012).”

“LENA currently has no automatic capacity to identify the contexts within environments like the preschool classroom (Irvin et al., 2017), and the technology still awaits improvement in measuring language quality features (Cartmill et al., 2013; Rowe, 2012).”

“Hearing fewer total and fewer diverse words leads to compromised expressive vocabulary at school-entry, which can have lasting impacts on children’s language, literacy and academic trajectories (Rowe, 2012).”

“, books and book-reading activities), prootes children’s vocabulary and grammatical knowledge (Farver, u, Lonigan, & Eppe, 2013; Hirsh-Pasek et al., 2015; Hoff, 2003; owe, 2012; Rowe, Leech, & Cabrera, 2017; Tompkins, Bengochea, icol, & Justice, 2017), which may in turn support successful anguage learning processes.”

“vocabulary) even more than sheer quantity (Cartmill et al., 2013; Goldin-Meadow et al., 2014; Huttenlocher et al., 2010; Rowe, 2012).”

“…complexity and syntactical structure, have consistently been shown to vary with SES (Huttenlocher, Waterfall, Vasilyeva, Vevea, & Hedges, 2010; Rowe, 2012) and may play a role in the development of EF (Noble et al., 2005; Sheridan, Sarsour, Jutte, D’Esposito, & Boyce, 2012; Rosen et al.,…”

“Both the quantity of words directed to the child and their quality appeared to be affected by socioeconomic disparities so that highly educated parents use more rare words and decontextualised utterances than those with low education (Rowe, 2012).”

“In particular, the amount of early language input from caregivers predicts language development later on (e.g., Hart & Risley, 1995; Hoff, 2003; Huttenlocher, Haight, Bryk, Seltzer, & Lyons, 1991; Rowe, 2012).”

“…not completely unexpected, as several longitudinal studies have demonstrated long-lasting socioeconomic disparities in children’s language skills (Hart & Risley, 1995; Huttenlocher, Waterfall, Vasilyeva, Vevea, & Hedges, 2010; Rowe, 2012; Uccelli, Demir-Lira, Rowe, Levine, & Goldin-Meadow, 2018).”

“An ensuing linguistic decontextualisation emerged when infants are in the verbal stage (Rowe, 2012).”

“But even after controlling for SES, the quantity and quality of language input has been found to be significantly associated with language abilities (Rowe, 2012; Weisleder and Fernald, 2013).”

“The presence of good quality language is crucial for educational potential (Rowe, 2012).”

“In studies on monolingual children, density of types rather than tokens is a better predictor of vocabulary learning (Dickinson & Porche, 2011; Pan et al. 2005; Rowe, 2012).”

“Prior literature indicates that the quantity of linguistic input has a positive association with children’s vocabulary development (e.g., Rowe, 2008, 2012).”

“…was directed to the child—namely, whether it was CDS—or else whether the speech was merely overheard but not addressed to the child in any way, is a major distinction in consideration of the quality of language input (e.g., Fernald 2000; Rowe 2012; Shneidman et al. 2013; Wang et al. 2018a,b).”

“Higher-SES children are exposed to greater lexical diversity, more syntactic complexity, and a larger proportion of conversation-eliciting questions (Hart & Risley, 1995; Hoff, 2006; Hoff-Ginsberg, 1991; Huttenlocher et al. , 2010; Rowe, 2012; see Schwab & Lew-Williams, 2016b, for a recent review).”

“Surely, the amount of exposure to words matters (Hart & Risley, 1995; Rowe, 2012), as does the quality of language interaction children experience (Hirsh-Pasek et al. , 2015; Rowe, 2012).”

“…of language input in the child’s environment has been long established as crucial for the pace of language development (Goodman et al., 2008; Rowe, 2012; Hoff, 2013; Gollan et al., 2015), receiving less input in the home language may cause setbacks in developing comprehension and…”

“2002; Rowe 2012), contributing to the ‘wordgap’ phenomenon of contemporary interest (Hindman et al.”

“…Hirsh-Pasek et al., 2015; Huttenlocher, Haight, Bryk, Seltzer, & Lyons, 1991; Rowe, 2012) and the emergence of complex sentences (Huttenlocher, Vasilyeva, Cymerman, & Levine, 2002; Huttenlocher, Vasilyeva, Waterfall, Vevea, & Hedges, 2007; Rowe, 2012; Vasilyeva, Waterfall, & Huttenlocher, 2008).”

“For example, both men and women change their voice when speaking to infants (Foulkes et al., 2005; Broesch and Bryant, 2015) and this specific infant-directed speech affects attention and communicative outcomes of the children (Rowe, 2012; Spinelli et al., 2017).”

“This would be consistent with developmental trajectories of the variable influence of language input, in which quantitative measures are most important for young infants, while qualitative measures become increasingly more important as children age (Rowe, 2012; Rowe & Snow, 2020).”

“…are able to converge on a shared topic, be it an event in the here and now, a reminiscence about a past episode, or a discussion of future plans (Rowe, 2012); in the context of make-believe play, they are able to enact a joint fantasy, understanding and complementing their partner’s pretend…”

“Similar effects of early exposure to speech on later outcomes are observed in children’s vocabulary size (Hart & Risley, 1995; Pan et al., 2005; Rowe, 2012).”

“…of word-referent mapping (Cartmill et al., 2013; Smith, Suanda, & Yu, 2014), the contributions of the environment and the learner to vocabulary development (e.g., Bornstein, 1985), and the sources of inter-individual differences that pervade research on lexical development (e.g., Rowe, 2012).”