An Association Between Phonetic Complexity of Infant Vocalizations and Parent Vowel Hyperarticulation

Abstract

Extreme or exaggerated articulation of vowels, or vowel hyperarticulation, is a characteristic commonly found in infant-directed speech (IDS). High degrees of vowel hyperarticulation in parent IDS has been tied to better speech sound category development and bigger vocabulary size in infants. In the present study, the relationship between vowel hyperarticulation in Swedish IDS to 12-month-old and phonetic complexity of infant vocalizations is investigated. Articulatory adaptation toward hyperarticulation is quantified as difference in vowel space area between IDS and adult-directed speech (ADS). Phonetic complexity is estimated using the Word Complexity Measure for Swedish (WCM-SE). The results show that vowels in IDS was more hyperarticulated than vowels in ADS, and that parents’ articulatory adaptation in terms of hyperarticulation correlates with phonetic complexity of infant vocalizations. This can be explained either by the parents’ articulatory behavior impacting the infants’ vocalization behavior, the infants’ social and communicative cues eliciting hyperarticulation in the parents’ speech, or the two variables being impacted by a third, underlying variable such as parents’ general communicative adaptiveness.

Infant‐directed speech does not always involve exaggerated vowel distinctions: Evidence from Danish

“…For example, IDS stimuli can facilitate neural processing (Peter et al, 2016), induce faster word recognition (Song et al, 2010), and produce better word segmentation of an artificial language composed of nonsense syllables (Thiessen et al, 2005). The extent to which parents produce acoustically exaggerated vowels in IDS has been shown to have an effect on concurrent speech discrimination skills (García‐Sierra et al, 2016, 2021; Liu et al, 2003), later expressive vocabulary (Hartman et al, 2017; Kalashnikova & Burnham, 2018), and the complexity of vocalizations at a later point in time (Marklund et al, 2021). Other descriptive studies showed positive correlations between pitch modulations in IDS and expressive vocabulary size (Porritt et al, 2014; Rosslund et al, 2022; Spinelli et al, 2017).…”

Infant-Directed Speech Does Not Always Involve Exaggerated Vowel Distinctions: Evidence From Danish

“…For example, IDS stimuli can facilitate neural processing (Peter et al, 2016), induce faster word recognition (Song et al, 2010), and produce better word segmentation of an artificial language composed of nonsense syllables (Thiessen et al, 2005). The extent to which parents produce acoustically exaggerated vowels in IDS has been shown to have an effect on concurrent speech discrimination skills (García-Sierra et al, 2016Liu et al, 2003), later expressive vocabulary (Hartman et al, 2017;Kalashnikova & Burnham, 2018), and the complexity of vocalizations at a later point in time (Marklund et al, 2021). Other descriptive studies showed positive correlations between pitch modulations in IDS and expressive vocabulary size (Porritt et al, 2014;Rosslund et al, 2022;Spinelli et al, 2017).…”