Patients with left-side brain damage who can no longer speak can find they are able to sing words, often without trouble or training. After that, it's just a matter of time before they're able to speak simple sentences with practice. That may not sound like much, but if you've ever tried to order a side of fries with left-hand only charades you'll understand what a blessing this can be.
How Does it Work?
Melodic intonation therapy, or singing until you can talk, takes advantage of the fact that language functions are located in the left brain, but music lives over on the right side of the brain. So, when that asshole stroke robs you of your ability to speak, you can train your brain to move those functions to the other side by associating music with language. This essentially rewires a lifetime of growth and an entire history of evolution into meaninglessness interpretations of random head noises from a guy who hasn't shaved his beard since the 70s.
Listening to actual non-terrible music has an additional effect, since pleasurable music releases dopamine that simply makes certain parts of your brain function better (particularly if they were damaged before).
Dopamine is your brain's natural crack