In The Lord of the Rings, Gollum has two distinct personalities: Sméagol and Gollum. Sméagol is good while Gollum is evil. The two personalities frequently talk to each other, giving the impression of Gollum talking to himself. (This is even more apparent in the movies, where Sméagol speaks in a softer tone while Gollum speaks in a harsher tone.)