The role of accommodation in expressing emotions to newborn babies

Infant-directed speech (IDS) carries signals expressing strong positive emotions towards the baby. This has been shown in various studies for e.g. higher f0 and energy, lower speech rate etc. Longitudinal studies comparing adult-directed (AD) and ID speech revealed that the difference between acoustic features usually connected with strong and positive emotions were not present directly from birth in mothers’ speech, but emerged only at a later time point. In this study, emotion expression in terms of arousal and valence was investigated through labellers’ perception in two groups: primipara mothers giving birth to their first child, and multipara mothers who were already experienced in IDS with their older children. A set of fixed sentences taken from semi-spontaneous speech was scored by labellers. Both arousal and valence scores were higher in IDS. Arousal scores were further apart in the multipara group, while this distinction was not present for valence. A set of acoustic parameters were investigated according to low and high perceived arousal and valence in the same data set.