Hitting

My two year old thinks it’s hilarious to hit me. I tried calmly telling him why it’s not okay to hit and that it hurts mama but he literally cracks up when he does it and doesn’t listen to me. I yelled at him out of anger because he keeps doing it and I try my hardest not to yell but I snap sometimes and I feel bad about it. Honestly the yelling was the only thing to make him stop laughing about it but I don’t know what to do! He’s got a speech delay and seems to understand everything but doesn’t seem to understand when I tell him no it’s not funny it hurts. Any advice on what to do? This is so frustrating