My Husband Was Talking To Me On Sunday When He

My husband was talking to me on Sunday when he got stuck saying the work I. I took him to the er. They ran a cat scan, a cat scan with dye, an MRI, and a angogram of the heart. Everything came back normal. His speech is still not correct. He know what he wants to say, but can not get the words out. Some will come out and some will not. He can write it down, but has a hard time saying them. He has a little right side weakness in his hands and legs. There is no droop to eyes or mouth. Any ideas what is wrong?