La-la theory (also called the sing-song theory) is the name of one of the speculative theories about the origins of language. This theory claims that speech originated in song, play, laughter, and other aspects of romantic side of life. It also argues some of our first words were long and musical rather than short grunts some theories suppose we started with.
Have you ever thought or read about the origins of speech? There are some other theories in addition to this theory. But, I like this one very much. It is a very neat and lovely theory, anyway.