| Popis: |
The current study will examine the acoustic properties of infant-directed speech (IDS) to 8-month-old Norwegian infants, and will assess whether these properties, or the (articulatory) adaptation 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 infants' emerging language, as indexed by both parent report (CDI) and an eye-tracking experiment (IPL) of word comprehension. In a previous study with 18-month-old toddlers in Northern Norway, Rosslund et al. (2021) found that IDS is characterized by increased pitch, pitch range and vowel duration, as well as vowel space expansion, yet, more variable vowel categories. It was also found that parents' hyper-pitch, and low vowel category variability in IDS, was associated with expressive vocabulary size. The current study aims to assess the same properties of Norwegian IDS as in the previous study (Rosslund et al., 2021), directed this time to 8-month-old infants growing up in Oslo and exposed to Eastern Norwegian dialect, and whether there are associations between the above-mentioned features of parents' speech (supplemented with additional measures, see section 'Design Plan') and infants' language development (e.g., Hartman et al., 2017; Kalashnikova & Burnham, 2018; Rosslund et al., 2021), also when indexed by direct measures. The data was collected in a babylab in Oslo, Norway, and parents' input was recorded from the child's main caregiver who could be either child's mother or father. As compared to previous studies in Norwegian, the current sample had a balanced representation of both fathers and mothers. To avoid effects of linguistic variables, e.g., consonant 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. This pre-registration largely follows that of Rosslund et al., 2021 (https://osf.io/7st6w/) with 18-month-old toddlers, hence the study design and the analysis pipeline is the same. |
