Poster #112 - Mothers’ use of infant-directed vocabulary and its relation to children’s early language development

• In Event: 3-106 - Poster Session 11
  In Poster Session: PS 11 Section - Language, Communication

Integrative Statement

The way in which adults talk to infants is referred to as infant-directed-speech, which is characterized with higher pitch, wider pitch range, and shorter and simpler utterances. Furthermore, some Japanese adults use ikujigo, infant-directed vocabulary (IDV), only when they talk to infants. In ikujigo, onomatopoetic (e.g., wanwan ‘bowwow’ for inu ‘dog’) or reduplicated (e.g., kuQku for kutsu ‘shoe’) words are frequently used instead of regular adult forms. Although some researchers pointed out that infants easily segment IDV words from fluent speech (Hayashi & Mazuka, 2006) due to their heavy-light rhythmic pattern (Mazuka et al., 2008), some childrearing specialists recommend mothers not to use those words since children finally need to replace once-learned IDV words with adult form words.
We hypothesized that a mother fine-tunes the use of IDV words to age and language level of the child, and helps the child smoothly transit from IDV words to adult form words. The present research investigated longitudinally how mothers’ use of IDV words changes as their children grow up, and whether mothers’ use of IDV words is related with children’s early vocabulary size.
Fifty two mothers answered a IDV-word questionnaire when their children were 10, 12, 15, 18, 21, and 24 months old, and also filled out Japanese MacArthur Communicative Development Inventory (Japanese CDI, Ogura & Watamaki, 2004) when their children were at 18, 21, 24 months. In the IDV-word questionnaire, mothers were presented with 220 nouns extracted from Japanese CDI, and asked whether they use an adult form word or an IDV word for each item. The number of items for which an IDV word was used was counted for each mother as an IDV score.
Figure 1 shows mean IDV scores as a function of children’s age. Mothers increase use of IDV words from 10 to 18 months and decrease it from 18 to 24 months. Mothers thus fine-tune their IDV-word use to the development of their children. At the same time, correlational analyses suggested that individual difference in IDV-word use was fairly stable. Correlational coefficients ranged from .273 (between 12 and 24 months, p =.051) to .846 (between 15 and 18 months, p = .000).
Next, we calculated correlational coefficients between mothers IDV-word use (at each time point and mean, maximum, and range of number of items for which IDV words were used) on one hand and the number of words children produced at 18, 21, and 24 months on the other (Table 1). Mothers’ use of IDV words at 12, and 15 months was positively related with children’s vocabulary at 18, 21, and 24 months. Furthermore, not mean, but maximum number and range (maximum number minus minimum number) of IDV-word use by a mother positively correlated with the child’s early vocabulary, suggesting that not IDV-word use per se but mothers’ sensitivity to their children’s developmental level may foster children’s word learning.

Author

• Etsuko Haryu, University of Tokyo
  Presenting Author