A few of my clients talk the entire session. I listen and let them talk as much as they want. It was a little hard at first (years ago) to keep up with their conversation and keep my mind on their workout. But now it is no problem. I actually find it a nice relief from clients that expect me to talk and keep them entertained/distracted/in the moment/etc. And for many of them, it seems to relieve their stress from their lives, work, families, etc.
But if that isn’t your client fit, I would consider referring them to another trainer. If you don’t like the talkative client, it will wear on you. Or you could try to enjoy it from another viewpoint.