What is overextension and underextension speech in children?

Question

What is overextension and underextension speech in children?

Answer 1

Overextension is when a child uses a word too broadly.  Like if they called ALL males 'daddy' or all aniamls 'dog'...It's not because the child doesn't detect differences, though, it's because they don't have other words to use yet.

Underextension is the opposite.  For example, a child may only call black labs 'dog' but no other dogs.  Or calling their rattle a rattle, but calling other ones 'toys'.