The scope of audience design in child-directed speech: Parents’ tailoring of word lengths for adult versus child listeners.

Abstract

When communicating with other people, adults reduce or lengthen words based on their predictability, frequency, and discourse status. But younger listeners have less experience than older listeners in processing speech variation across time. In 2 experiments, we tested whether English-speaking parents reduce word durations differently across utterances in child-directed speech (CDS) versus adult-directed speech (ADS). In a child-friendly game with an array of objects and destinations, adult participants (N = 48) read instructions to an experimenter (adult-directed) and then to their own 2- to 3-year-old children (child-directed). In Experiment 1, speakers produced sentences containing high-frequency target nouns, and in Experiment 2, they produced sentences containing low-frequency target nouns. In both CDS and ADS in both experiments, speakers reduced repeated mentions of target nouns across successive utterances. However, speakers reduced less in CDS than in ADS, and low-frequency nouns in CDS were overall longer than low-frequency nouns in ADS. Together, the results suggest that repetition reduction may be beyond speaker control, but that speakers still engage in audience design when producing words for relatively inexperienced listeners. We conclude that language production involves nested audience-driven and speaker-driven processes.

Prosodic modulations in child‐directed language and their impact on word learning

“…Even in child-directed speech, caregivers reduced word duration for second mentions (Bortfeld & Morgan, 2010), although the extent of the reduction has been shown to be smaller in CDS than ADS (Tippenhauer et al, 2020). However, our results for pitch are inconsistent with the findings of Bortfeld and Morgan's (2010) study, in which caregivers did not reduce the mean pitch or pitch range significantly in the second mentions compared to the first mentions.…”

“…These results are consistent with past research showing that the accessibility of a referent can greatly impact word duration and that speakers tend to produce a word with a pitch accent when it is mentioned for the first time, but deaccent the same word in subsequent mentions (e.g., Fisher & Tokura, 1995; Fowler & Housum, 1987). Even in child‐directed speech, caregivers reduced word duration for second mentions (Bortfeld & Morgan, 2010), although the extent of the reduction has been shown to be smaller in CDS than ADS (Tippenhauer et al., 2020).…”

“…In CDS, Tippenhauer et al. (2020) also found that caregivers reduced word duration for repeated mentions, although the extent of the reduction was less in CDS compared to ADS. However, a study by Bortfeld and Morgan (2010) showed that first mentions were longer in duration than second mentions in CDS, but mean pitch and pitch range was not reduced.…”

“…A large body of literature has focused on the differences between CDS and ADS (e.g., Han et al., 2020; Kalashnikova & Kember, 2020; Ma et al., 2011; Tippenhauer et al., 2020; Wang et al., 2021), but research on how prosody is modulated within CDS and how such modulations may affect learning remains largely unexplored. In this paper, we focus on caregivers’ prosodic adjustments (speaking rate, pitch, and intensity) in communicative contexts where such adjustments could be especially useful, namely, when learning new words and when learning is more difficult because the referent is not physically present.…”

Multimodal language in child-directed versus adult-directed speech

“…According to this analysis, regardless of the task, participants use more words in CDS compared with ADS. Similar studies show that adults use more words towards child addressee because children are less experienced (Tippenhauer et al, 2020). Our findings may indicate that adults use more words by giving detailed explanations to children as they are less experienced.…”