What causes an person with Alzheimer's to constantly talk and mumble?

What causes an 80 year old alzheimers patient to start mumbling 24/7, sometimes even when she is asleep? I've learned that benadryl allergy meds causes major interaction with her meds. I'm trying to find out if Ocuguard Plus Eye Med Supplement is causing an interaction as well. Anyone else go through this? It seems to be going on for about a month now and that on top of sundowning, omg. Any help you can provide would be awesome! Thanks so much.