As you can see by the many posts, you are not alone in this, and there are many solutions. I for one am a believer in ghosts and angels. My daughter, now 3.5y started having conversations in her room when she was 2. She even went as far as to introduce my sister to her friend. Mind you Auntie was very freaked out. We would lay in bed and hear her having a conversation, no responses luckily. Sometimes she fights over a toy, sometimes she cries. She now has an imaginary friend that she calls her sister. On these nights I am the one to go soothe her. Hubby is totally freaked.
I go into her room to make sure she's okay, and ask her what happened. If she says that she is fighting with her sister, I tell her that no one should be fighting, you should be sleeping. I have her then say goodnight to her room. 'Good night room, good night toys, good night friends whereever you are'... Sometimes she says that there is someone mean that is trying to take her toys. I tell her, well you just tell them that your mom doesn't allow mean people over to play so they have to leave. One night she had several bad wakeups. I just wanted to sleep. I was so tired that I went into the room and said very loudly, 'I am tired. Its 2 am, and way past playtime, if this room does not calm down and go to sleep everything in this room it will be in timeout! I put her in bed and she stayed asleep for the rest of the night.
While you may think I'm crazy for playing along, I don't see it as that. I see it as showing her how to cope with whatever her brain is or thinks it is seeing. I do believe that there are 2 possibly 3 ghosts that visit my house. The events that have happened make me think that its family. I have noticed that the amount of episodes vary, and are worse around birthday's and father's day. Again hubby won't talk about it.