Voice quality modifications in Hungarian infant-directed speech: A longitudinal acoustic study

Adults exhibit different acoustic characteristics in infant-directed speech (IDS) compared to adult-directed speech (ADS). We investigate differences in voice quality between IDS and ADS in sentences read aloud by Hungarian mothers, using longitudinal data gathered at various child ages (4, 8, 18 months). Vowels in IDS are found to be breathier than those in ADS, regardless of the infant's age. Possible motivations for this difference may include emotional expressions, as breathiness relates to positive emotions, and speech entrainment, since the speech of children is breathier than that of adults.