I'm the father of a language delayed 3 year old. She's cognitively normal in all other respects.

Recently it's becoming more important to get her to understand the concept of "why", but we can't seem to make her understand. Things like asking her why she did something, she doesn't seem to understand the question. She can tell us what she did, or show us how she did it, for example, but never even the beginnings of why.

I also don't think I've ever heard her ask why, which is one reason I don't think she comprehends it.

Does anyone have any suggestions on how to begin teaching that concept to a 3 year old? Especially one who lags behind in language skills in general?