Reification of infant-directed speech? Exploring assumptions shaping infant-directed speech research

Abstract

The seemingly ubiquitous tendency of caregivers to speak to infants in special ways has captivated the interest of scholars across diverse disciplines for over a century. As a result, this phenomenon has been characterized in quite different ways. Here, we highlight the shift from early definitions of “baby-talk” which implied that the nature of speech directed towards infants would vary in different sociolinguistic contexts, to later terms such as “motherese” or “infant-directed speech” (IDS) which came to refer to a specific set of features, some of which were argued to represent a universal, optimal and culturally invariant form of speech. These divergent conceptualizations of IDS thus reflect broader disciplinary tensions pertaining to the role allotted to cultural processes in psychological research. We hope to contribute to this literature by pointing to the complexity associated with identifying discrete categories of speech (i.e., baby-talk and motherese/IDS) within a complex multi-dimensional sociolinguistic landscape. We also highlight ways in which a lack of attention to the cultural context of infant-caregiver interactions may have led to biased characterizations of IDS. Furthermore, these biases may implicitly penetrate the nature of empirical work on IDS as well. We end with a series of suggestions for future directions.

Does child-directed speech facilitate language development in all domains? A study space analysis of the existing evidence.

“…The pivotal measure of mean length of utterance has only been compared in one study (Ko et al, 2020) which used two ADS registers for comparison, a less formal one directed at a family member and a more formal one directed at the experimenter. Interestingly, this study found that syntactic complexity was lower in CDS compared to informal but not to formal ADS, an intriguing finding suggesting that the familiarity confound plaguing many CDS-ADS comparisons (Weinstein & Baldwin, 2022) may, in fact, have led to an underestimation of differences between CDS and ADS, a suggestion that certainly needs further investigation. A few other studies have focussed on comparing overall utterance length (Kaye, 1980;Lee et al, 2008;Martin et al, 2016;Vigário et al, 2006) but often with the goal of explaining the origins of certain prosodic and phonological characteristics of CDS as a by-product of utterance-length differences.…”

Studying Child-Directed Speech

“…However, to ascertain what role features that distinguish CDS from ADS may play in language development it is necessary to examine their effects on learning gains, as we will discuss in Section 3. A deeper understanding of the function of CDS also benefits from comparing it to ADS sampled from a greater variety of contexts and situations (Weinstein & Baldwin, 2022), and to other forms of speech directed at different addressees like foreigner-directed speech (e.g., Piazza et al, 2022), pet-directed speech (e.g., Burnham et al, 2002) or elderspeak (e.g., Kemper & Harden, 1999).…”

“…play time, meal time, grooming and bed-time routines) differ markedly from the situational contexts in which adults tend to interact with each other. In most studies, ADS corpora tend to differ in context and content and therefore introduce a range of situational and contextual confounds into the comparison (Weinstein & Baldwin, 2022. Even if children and adults are placed in similar situations, speech to young children tends to focus on the here and now while adults often talk about topics displaced in space and time (Foushee et al, 2023).…”

“…To date, a disproportionate emphasis on play with toys and picture-book reading in laboratory studies and on dyadic mother-child interactions may have provided a distorted picture that misses the diversity of communicative situations in which infants and young children acquire language. Moreover, comparison of childdirected to adult-directed communication is often restricted to a few standardized adult interactions (e.g., interviews between mothers and experimenters) which are of limited ecological validity and do not even come close to capturing the broad variety of adult communication (Weinstein & Baldwin, 2022). In addition, the existing comparisons between CDS and ADS tend to focus on a few domains of language, mainly prosody and phonology, at the expense of others, including morpho-syntactic, lexico-semantic, and pragmatic features.…”

“…He suggested that these words serve two functions: to evoke nurturant behaviors and to aid language learning (Ferguson, 1964). Because of the characteristic differences to adult-directed speech (ADS), the term CDS typically came to denote not just the language that is directed at children but a distinct way of speaking, akin to a speech register (but see Saxton [2008] and Weinstein & Baldwin [2022] for a critical analysis of the applicability of this sociolinguistic concept to CDS). The conceptualization of CDS as a distinct form of speech sparked a prolific line of research into the features of CDS, the factors that influence the propensity of caregivers to modify their language when addressing small children and the effects of these modifications on language development.…”