Children from disadvantaged families tend to have limited language skills compared to their advantaged peers. While many factors contribute to language ability, two aspects of the early caregiving environment are known to be correlated with child language outcomes 1) caregiver-child book reading and 2) caregiver contingent talk. Contingent talk refers to a style of communication whereby the caregiver talks about what is in their infant's current focus of attention. This style of talking can be facilitated when parents read books with their babies. The aim of this research is to establish whether asking parents to engage in contingent talk in the context of book reading promotes vocabulary learning. This study will compare the effects of an intervention to promote contingent talk against a control where parents are given books but not given any training in how to read them in a contingent manner. The study will include children from socio-economically advantaged and disadvantaged families.