Question

A child says, "kitty walk," and the parent answers, "yes, the kitty is walking." this is an example of

Answer 1

A child says, "Kitty walk," and the parent answers, "Yes, the kitty is walking." this is an example of expanding.
Expanding in terms of talking to the child , will help the child to  expand vocabulary, to develop background knowledge, and inspire a curiosity about the world.