Hi, all kids develop differently but I would be getting him checked out by your health nurse or GP, especially with his speech. If he's not able to communicate well, this could be why he's not sharing, not using manners or having tantrums when you leave somewhere. Also have you had his hearing checked? If everything is fine health wise, they'll be able to give you some pointers plus a 'problem' shared is a problem halved as the saying goes, if you're at your wits end it will be good to be able to chat to someone about your concerns.
I agree - get him checked out to make sure everything is ok. I would make sure he is fully assessed and if you're not satisfied, get a second opinion. Also a hearing check is a good idea, as Kristen said.
Once you have ruled out with 100% certainty any developmental issues, physical or psychological, then you will need to think of other ways to deal with it. But at least you will know for sure it's a disciplinary issue as opposed to a health issue.