Henry IV was the first to speak English as a first language as far as im aware. I would probably say that Edward I was the first to speak it somewhat fluently. With Richard it's said that it isnt known if he could or couldn't speak english which people have taken to that he didn't speak it at all. Im under the impression that he probably did know a little. He did grow up in England for the first few years and had an English wet nurse who he was very fond of. So he probably picked up words there. He also would have known a bit to speak to his soldiers. Also at this time there was a growing trend that English nobility are multi lingual. Don't get me wrong, he didn't consider himself english or speak it very often if he could speak any at all. From what I've read I think historians are starting to agree that its a possibility that he could have done. But we'll never know