Hi, thanks for writing in, and good question! Some people lose the ability to speak in what’s called “aphasia,” but this doesn’t sound like it is entirely the case here. Even if she can still read, she may have some difficulty speaking (or understanding). Your mom may have some difficulty finding the right words, so she’s afraid of making a mistake in conversation with you. She may also have some difficulty understanding. Are you speaking slowly and loudly enough?
Music stays with people. Music affects many different parts of the brain, and some of these areas are not damaged in dementia. My residents LOVE to sing.
I wonder if you could bring in a CD player and you all could listen to some of her favorite songs. I bet that she’ll be able to tell you about them and how it makes her feel.