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 play. Variation in these specific characteristics of fathers' speech that differed across contexts was also positively associated with child vocabulary skill measured on the MacArthur-Bates Communicative Development Inventory. Results are discussed in terms of how different contexts elicit specific qualities of child-directed speech that may promote language use and development.