My mother is having conversations with someone in her room that is not there.

Your profile says Mom has dementia. Seeing or believing in people who aren't there is not unusual in people with dementia. If this is a new symptom discuss it with her doctor. If this behavior does not bother her there is no need to treat it. If she is frightened and talking to a Bad Guy, that is different. But if she is just having pleasant conversations that is not a huge concern.

I sometimes talk out loud to myself. I have no delusion that someone is there -- I'm only talking to me. These are not long conversations but I sometimes ask a question and answer myself. Are you sure your mom is talking to her hallucination or delusion?

My mother talks to my dead father in her room each night. Sometimes she will talk to him for an hour or two while sitting on the side of her bed, looking at his picture. She tells him all the events of the day and all the things bothering her. Funny enough, sometimes she even tells him lies about things that happen. When she started doing it, I thought it was a little odd. Now I just realize it is something she does. She knows he's not really there, though. Maybe she thinks he can hear her, but tells me that she knows he can't because she doesn't want me to think she's crazy.

Do you know who it is that your mother is talking to? My mother has dementia, so her behavior is rarely what you would expect.

That is called "hallucinations". Call the MD and get mom checked out.