However, if while reading a story together, you notice that your preschooler shows curiosity about the actual letters on a page, encourage her interest. Say aloud the sounds that the letter makes. Name some words that begin with the letter. Then, point out more examples of the letter in print--in other books, magazines, on street signs, and so on.
Show her how the same letter appears in different sizes and fonts and in uppercase well as lowercase. Demonstrate how you print the letter on paper, where it lives on a keyboard, and let your preschooler try her hand at writing the letter.
Then, if your preschooler seems to lose interest in this discussion, drop it immediately, and get back to your story!