Prior research shows that shared book reading promotes preschoolers´ language and literacy skills. However, little
is known about the potential role of books´ features –e.g., wordless picture books vs. books with text– in children and teachers´
spontaneous language production. In this study, we transcribed verbal interactions of thirteen Colombian teachers reading
to groups of preschooler students (aged 43 to 55 months) during reading sessions in Spanish using wordless picture books
(condition 1) and prototypical storybook with text (condition 2). Books were matched for page length, genre and theme. Using
Computerized Language Analysis (CLAN), we found important differences in children and teachers´ spontaneous language
production. Specifically, paired t-test comparisons revealed that in the wordless-picture-book condition: (a) children produced
significantly more word tokens, word types, utterances and questions (all p´s < .05), and (b) teachers produced significantly
more word tokens, questions and levels of instructional support (all p´s <.05).