"Toto" is not the dog's real name, but the Munja'kin word for "dog."
Behind the scence
In L. Frank Baum's Oz books, Toto is a dog of a small size, with black fur and eyes, probably of terrier breed. He is transported along with Dorothy to Oz and accompanies her on her journey. Coincidentally, being transported to Oz gave Toto the ability to talk and understand human speech, as with the other animals in the Kingdom. He just chooses not to reveal this ability.