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

The peculiar sound structure of Danish has been argued to reduce the salience of cues that allow infants to extract information from the speech stream. To assess whether caregivers adjust their infant-directed speech (IDS) to accommodate these processing challenges, this study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers’ spontaneous speech addressed to their 11-24-month-old infants and an adult experimenter. The data were collected between 2016-2018 in Aarhus, Denmark. Prosodic properties of Danish IDS conformed to cross-linguistic patterns, with a higher pitch, greater pitch variability and slower articulation rate than ADS. Crucially, though, vocalic properties contradicted cross-linguistic tendencies: Danish IDS was produced with a reduced or similar vowel space, higher within-vowel variability, and lower degree of vowel discriminability than ADS.