My mom no longer is able to read, is this normal for someone with moderate Alzheimer's?

Yes this inability to read does follow the pattern of Alzheimer's disease (AD) in the moderate stage. There are many facets to this particular ocurrence. Rather than a problem with pronunciation, the loss of the ability to read seems to be more a loss of comprehension combined with other losses caused by AD. As the brain deteriorates, cognition and intellect are slowly eroded, resulting in the AD person having difficulty with the following: * remembering what they have just read, * comprehending vocabulary, * decreased attention span, * and processing information. All of these items are necessary to be able to read and understand what is read and most likely your mom has been affected by them all. I would encourage you to read simple verses out loud to your mom and to share simplified stories and picture books with her. AD folks seem to enjoy the sound of rhyming poetry - you may find reading aloud to her to be quite fulfilling for you both. Do take good care of you.