The linguistic input a child receives in the first years of life is foundational for cognitive and language development. In a corpus analysis, the vocabulary in picture books was richer and more extensive than that found in child-directed and even adult-directed speech. The grammar and complexity of these communication media, measured by reading grade level, indicated that picture books averaged two grades higher than child-directed speech and one grade higher than adult-directed speech. These differences between written and spoken language can be more adequately described by formal versus informal genres rather than their oral or written media. Given that the child will read words and grammar not experienced in speech, these results question the feasibility of the popular view that a child’s reading task is simply to “decode” the written language into spoken language. A framework of acquiring literacy informally before schooling begins is described and explained.