It is widely recognized that there is a relationship between vocabulary development and children's reading ability. This article will focus on the strategies employed by 24 adults (12 mothers and 12 qualified preschool teachers) when introducing new and unusual vocabulary to four-year-old children during shared reading. The mothers differed in terms of educational achievement; half the mothers had left school by the age of 16, and half the mothers were tertiary educated. All the adult–child dyads read the same two picture books (one narrative and one informational) and the surrounding talk was analysed to determine what kinds of supportive strategies were used by the adults to introduce and explain unfamiliar vocabulary items. There were differences between the two groups of mothers in terms of the frequency and manner in which technical vocabulary was introduced and defined. The preschool teachers differed from both types of mothers. The implications of these findings for young children's emergent literacy are discussed.