Strange noises when eating

Hello,
My cat makes the strangest noises when she eats, but not all the time.
Actually she hasn't done this for quite some time and has recently started again.
Sometimes it sounds as if she is grinding her teeth or as if she has a squeeky sponge in her mouth. She makes this noise even if she is eating her can food.
I have also noticed when she eats her dry food, she leaves small pieces behind which she will not eat: this was typical before when she was have this aggravating experience.
She has not had any diet changes or life style changes recently and appears very healthy.
I wonder what it could be? Any ideas?
Looking forward to your reply.
P.S. Great site. Thanks for being here.
Hugs, Tdeb

[Aleda M Cheng, D.V.M., C.V.A]

Your should have her mouth, teeth,  and jaw checked by a veterinarian.  She may have dental disease, stomatitis, glossitis, gingivitis or peridontitis (infection of the tissues of the mouth such as gums, tongue soft and hard pallete, peridontal ligament, tooth roots etc).