Learning about letters, and how they differ from pictures, is one important aspect of a young child's print awareness. To test the hypothesis that parent speech provides children with information about these differences, we studied parent-child conversations in CHILDES (MacWhinney, 2000). We found that parents talk to their young children about letters, differentiating them from pictures, by 1-2 years of age and that some of these conversational patterns change across the preschool years in ways that emphasize important features of letters, such as their shape. We also found that children talk about letters and pictures in distinct ways, suggesting an implicit understanding of some of the differences between letters and pictures at an early age. Some differences in parent-child conversations about letters were found as a function of socioeconomic status: Lower SES families appeared to focus more on alphabetic order than higher SES families. The general letter knowledge expressed in these conversations suggests that everyday interactions are an important component of the home literacy environment and that they differ, in some respects, as a function of child age and family background.