We examined differences between children with autism spectrum disorder and typically developing children over an 8-month period in: (a) longitudinal associations between expressive and receptive vocabulary and (b) the extent to which caregiver utterances provided within an "optimal" engagement state mediated the pathway from early…

Fathers' child-directed speech across two contexts was examined. Father-child dyads from sixty-nine low-income families were videotaped interacting during book reading and toy play when children were 2;0. Fathers used more diverse vocabulary and asked more questions during book reading while their mean length of utterance was longer during toy…