Shared book reading is often used as an educational tool to promote the development of children’s early language and literacy skills. This study aimed to describe and compare the linguistic features of parent–child interactions during two shared book-reading sessions among 45 children (aged 4–6 years old) and their mothers. The dyads were divided into 2 groups: the intervention group ( n = 25), and the control group ( n = 20). In the first reading session, mothers read with their children the way they were most comfortable with and as they would usually do at home. Before the second reading session, we provided a 30-minute intervention on strategies of dialogic reading to the intervention group. Both readings were video-recorded. Mothers completed home literacy environment questionnaires. The results showed that even for mothers who were initially very skillful at reading with their children, this immediate intervention promoted a number of aspects of interactivity between mothers and their children, namely, the number of utterances, completion, open-ended, closed and labeling questions, and type token ratio by mothers, the number of utterances and initiated talk by children, and extra-textual talk and total number of turns by both mother and child. Mothers who received the intervention demonstrated more flexibility and more discursive styles, even though the intervention was short, and the time for them to practice was minimal.