How can I gently help my mother with her table manners?

My mother is late 70s, pretty fit and well for her life stage, but I can see her starting to struggle a bit with certain things. I am noticing her dining table manners getting pretty bad; mouth-full talking, posture a bit too hunched over plate, and eating kind of carelessly.

This is a bit petty and maybe it’s me being intolerant but I suspect she’d rather come across in a more gracious way.

I’d like to give her gentle and constructive feedback so she can change if she wants, but I know it could feel a bit crushing.

she’s always been capable, but I think she may be slightly neurodivergent. I guess some of this is inevitable with age and it may be early signs we’ll need to look after her more soon, but for now I’m thinking it’s a superficial awareness thing.

Welcome ideas on helpful ways to frame this so it’s not hurtful but is still clear!