<P> Sometimes baby - talk words are taken into adult speech . Examples are: </P> <Ul> <Li> "nanny" = "children's nurse" to distinguish from "hospital nurse". </Li> <Li> "didy" for "diaper", in USA usage . </Li> <Li> In Ancient Greek, "πάππος" ("grandfather") instead of expected * "ἄος" from Indo - European * h2éwh2os </Li> </Ul> <Li> "nanny" = "children's nurse" to distinguish from "hospital nurse". </Li> <Li> "didy" for "diaper", in USA usage . </Li>

When does a baby learn how to talk