I'm confused, is this normal?

He might have talked to you in the beginning because of the new excitement, and now he's gotten used to being with you. Yes it's normal.
If you let him know you'd like him to talk dirty to you again, he might love to start doing it again.

Wear some sexy, lacy thing and whisper in his ear. He'll probably start talkin' again.

Have you talked to him? If you start the dirty talk, maybe he'll follow. The times I've been in a relationship, it seems pretty normal after awhile for the sex to fizzle. You gotta take turns turning up the heat.