Echolalia: normal? When should it be grown out of?

[mrsbaffled]

I know a little boy who is 2 and a half who seems to have very little comprehension and won't answer a question, but repeats what you say to him. So if you say "do you want beans or potato?" he will either say nothing, and not even indicate what he wants, or repeat "beans or potato". I have only ever heard him put words together when copying (he can say quite long copied sentences), but otherwise only says single words.

My kids are well past this stage and I can't remember if this is a normal stage of development? If it is, then by what age would you expect the copying to have gone?