Not surprisingly, these linguistic features tend to be baby talk features of affection and control, not pedagogy. Unique to adult-adult conversations that express affection is the use of substitutions. In adult language to adults, these same lexical substitutions serve not as forms of pedagogy but as expressions of affection. Typically, this feat can be accomplished by ostensibly using language for some other purpose. Syntactically, adult speech is simpler, shorter, and even occasionally ungrammatical with the goal of facilitating a response from the child.
Adults also employ less obvious conversational techniques for maintaining social interaction.
They restrict the choice of topics. I thought that was the problem. While the sharing of information is indeed an important function of language, it is also the most neutral structurally. Strict conveyance of information does not require any special language forms. Throughout the baby talk literature, there are no baby talk features that are described exclusively as communicating information.