My DS is 2.5 years old and has delayed speech due to severe glue ear. He has come on a lot since this resolved and since starting nursery but he still won't answer yes to questions. He can say the word but just doesn't say it in response to a question. He'll either repeat the request or say 'me me' for example if I say do you want milk? I've tried waiting for him to reply but he gets very frustrated. Any tips on how to help? Thanks