Kids grow up so fast. Sometimes, I am missing when my daughter is just a little baby. Now, she's already three years old.
This is the stage where toddlers create their imaginary friends. Whenever my daughter is alone in her room, she's talking to herself or to her dolls like she is talking to somebody. It's pretty cute to listen to.
If you have a toddler like mine, don't be alarmed if you hear them talk to himself/herself. Be proud instead, because that means that your child's imagination and creativity is exploring the real world.. It's pretty normal in their age.