Volubility as a mediator in the associations between conversational language measures and child temperament

Despite support for the use of conversational language measures, concerns remain regarding the extent to which they may be confounded with aspects of child temperament, extraversion in particular.

This study of 161 twins from the Western Reserve Reading Project (WRRP) examined the associations between children's conversational language use and three key aspects of child temperament: Surgency (i.e., introversion/extraversion), Effortful Control (i.e., attention and task persistence) and Negative Affectivity (e.g., fear, anger, sadness). Child biological sex was considered as a possible moderating factor.

Correlational analyses were conducted between aspects of temperament during early school-age years (i.e., 7-8 years), as measured by the Children's Behavior Questionnaire-Short Form (CBQ), and six different measures of children's conversational language use: total number of complete and intelligible utterances (TCICU), number of total words (NTW), mean length of utterance (MLU), total number of conjunctions (TNC), number of different words (NDW) and measure D (i.e., a measure of lexical diversity). Values for NTW, TNC and NDW were derived both on the entire sample and on the first 100 C-units. Correlations between language and temperament were compared between girls and boys using the Fisher r-to-z transformation to examine the significance of potential moderating effects.

Children's reported variability in Effortful Control did not correlate significantly with any of the child language measures. In contrast, children's Negative Affectivity and Surgency tended to demonstrate positive, albeit modest, correlations with those conversational language measures that were derived from the sample as a whole, rather than from a standardized number of utterances. MLU, as well as measures of NDW and NTW derived from standardized sample lengths of 100 C-units, did not correlate with any measure of child temperament. TNC demonstrated an unexpected negative correlation with child Surgency when it was derived from a standardized number of C-units, but not when derived from the entire sample length. Child biological sex did not moderate the significant associations between language and temperament measures.

Overall, measures that control for volubility did not correlate significantly with child temperament; however, measures that reflected volubility tended to correlate weakly with some aspects of temperament, particularly Surgency. Results provide a degree of discriminant evidence for the validity of MLU and measures of type (i.e., NDW) and token use (i.e., NTW) when derived from a standardized number of utterances.