Children's self-regulation has been found to be related to optimal developmental outcomes; however, researchers are still investigating how cognitive and emotional regulation work together to explain development of self-regulation. This study investigated how children's private speech interacted with emotion regulation, conceptualized as effortful control, to predict children's emotionality. I also examined how private speech and effortful control may be different strategies of self-regulation that more fully explain the relation of parental emotion coaching philosophy to children's emotionality.

Preschool-aged children (n = 156) and their primary caregivers participated in this study. Parental emotion coaching was observationally measured as encouraging of negative emotion when discussing a time when children were upset. Children's non-beneficial private speech was transcribed and coded during a cognitively-taxing task. Children's effortful control (attention shifting, attention focusing, and inhibitory control) and negative emotion (anger and sadness) were measured using parent-report on the Child Behavior Questionnaire (CBQ).

It was found that children's parent-reported effortful control significantly mediated the relation between parent's observed emotion coaching philosophy and children's reported negative emotionality. Parents who did more emotion coaching had children reported to have greater effortful control and in turn were reported as less emotionally negative. While parental emotion coaching did not predict children's non-beneficial private speech, children who used less of the non-beneficial private speech were reported as less emotionally negative. Lastly, children's private speech and effortful control interacted to predict children's negative emotion. When children were low in effortful control they were high in negative emotion, regardless of how much non-beneficial private speech they used. However, children with higher levels of effortful control were reported as less negative when non-beneficial private speech was low.

This research supports the importance of considering both cognitive and emotional development together, because private speech and emotion regulation interacted to predict children's negative emotionality. In addition, parents who support and encourage negative emotions may aid children's effortful control.

This research further supports the importance of children's use of private speech in the classroom because non-beneficial private speech may be an additional cue for teachers and caregivers to know that a child needs assistance.