Dirty talk

When me and boyfriend have sex, I can't get him to dirty talk with me. I say things too him and he'll say nothing. Even little things like you like that? I i like to dirty talk and sometime I just want him to get a little naughty with it if ya know what I mean 😉 I've talked to him but he says I don't know what to say and tell him and he just never does it. He is amazing in bed, he just doesn't let himself go. How can I get him to do this for me ?