A.G.
Both of my boys (now ages 4 and 10) did exactly that anytime they were about to learn something new, like have a language explosion, learn to crawl or walk, or begin some new skill. Then as they got a bit older they just liked to talk sometimes. My 4 year old talks or sings himself to sleep each night, and if he wakes up in the middle of the night he will talk or sing himself to sleep again. Have fun listening to her! :-)