The purpose of this study was to determine if intentional communicative acts differed between the group of late talkers aged from 18 to 24 months, who might experience explosive language development after the appearance of the first word, and their caregivers and that of typical toddlers of the same age and their caregivers, focusing on the interactions in book-reading and play situations. This study was conducted in 12 pairs of late talkers aged from 18 to 24 months and their caregivers and 12 pairs of typical toddlers that matched the chronological age and their caregivers, all of whom resided in Seoul, Gyeonggi-do, Incheon, and Daejeon. To collect data, the researcher paid visit to homes of the toddlers, or the toddlers and their caregivers visited the designated institution. The interactions between the toddlers and their caregivers in both book-reading and play situations were recorded using a camcorder for 10 to 15 minutes; then, the data from both situations were analyzed for the 5-minute intentional communicative acts with positive interactions between them. Total frequency of intentional communicative acts and that of each function of communicative acts were measured for both the toddlers and their caregivers in
the behavior sample. The data were processed by using an SPSS 19.0 program to perform repeated measures two-way ANOVA with the conditions and group as independent variables and with frequency of intentional communicative acts between the toddlers and their caregivers as dependent variables and to carry out Pearson''s correlation analysis with the objective of assessing the correlation of
intentional communicative acts between the toddlers and their caregivers in each group in terms of the conditions.
The results of this study are as follows: First, as for total frequency of intentional communicative acts in general
for the toddlers by the conditions and group, group had main effects: the late talkers more frequently showed intentional communicative acts than the typical toddlers. The conditions also had main effects: toddlers more frequently showed intentional communicative acts in the situation of book-reading than in that of play. There was no interaction effect between group and the conditions; that is,
the toddlers in both groups more frequently showed intentional communicative acts in the situation of book-reading. Second, as for frequency of each function of intentional communicative acts for the toddlers by the conditions and group, group had main effects only in terms of naming/stating, excepting demanding, imitating, questioning, and responding, among the five functions. This result implies that the late talkers more frequently showed intentional communicative acts than the typical toddlers in terms of naming/stating. The conditions had main effects only in terms of demanding, excepting naming/stating, imitating, questioning, and responding. This
result implies that the toddlers more frequently showed intentional communicative acts in the situation of book-reading than in that of play. There was no interaction effect between group and the conditions; that is, the toddlers in both groups more frequently showed intentional communicative acts in terms of demanding in the situation of play and in terms of naming/stating, imitating,
questioning, and responding in that of book-reading. Third, as for frequency of intentional communicative acts for the
caregivers by the conditions and group, group had no main effect: frequency of intentional communicative acts in general for the late talkers'' caregivers was similar to that for the typical toddlers''s caregivers. The conditions had main effects: they more frequently showed intentional communicative acts in the situation of book-reading than in that of play. There was no interaction effect between group and the conditions; that is, the caregivers in both groups more frequently showed intentional communicative acts in the situation of book-reading. Fourth, as for frequency of each function of intentional communicative acts for the caregivers by the conditions and group, group had main effects only in terms of feedback, excepting attention-calling, explaining, directing, and questioning, among the five functions. This result implies that the typical toddlers'' caregivers more frequently showed intentional communicative acts than those of the late talkers only in terms of feedback. In contrast, the conditions had main effects in terms of attention-calling, explaining, directing, and questioning, excepting feedback. Of these, they more frequently showed directing in the situation of play than in that of book-reading and attention-calling, explaining, and questioning in the situation of book-reading than in that of play. There were interaction effects between group and the conditions in terms of directing: frequency of directing in the situation of book-reading was similar to that in the situation of play for the late talkers'' caregivers, whereas those of the typical toddlers more frequently showed directing in the situation of play than in that of book-reading.
Fifth, as for the correlation between toddlers''s speech and intentional communicative acts of the toddlers and their caregivers in book-reading and play situations, the late talkers'' speech was negatively correlated with their
caregivers'' directing and the typical toddlers''s intentional communicative acts and speech were positively correlated with their caregivers'' feedback in the situation of book-reading. In the situation of play, neither the late talkers nor their caregivers showed correlation in intentional communicative acts and the typical toddlers''s intentional communicative acts were negatively correlated with their
caregivers'' attention-calling. This result implies that in the situation of book-reading, the more frequently the late talkers'' caregivers use directing, the less frequently the toddlers may make speech; the more frequently those of the
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