Properties of infant-directed speech and its relation to expressive vocabulary in 18-month-old toddlers in Northern Norway

Abstract

The current study will examine the acoustic properties of infant-directed speech (IDS) to 18-month-old Norwegian toddlers, and will assess whether these properties, or the (articulatory) effort that parents make when speaking IDS as compared to adult-directed speech (ADS), i.e., the acoustic differences between the two registers, are related to toddlers' expressive vocabulary size. The data was collected in Tromsø, Norway, from parents speaking a Northern Norwegian dialect, and parental input was recorded in the lab, from the child's main caregiver that could be either child's mother or father. To avoid effects of linguistic variables, e.g., consonantal context (known to influence vowels, see Steinlen & Bohn, 1999; Steinlen, 2005), between the two registers, both IDS and ADS were elicited via a storybook reading task