Pretty cool concept !
If I understood correctly from your description, the letters are randomly generated, right? so that means that the melody is also randomly generated based on the letters you get ? because I kinda liked some melodies and it's pretty neat if it's all random!
My only issue was that I felt like the game was too easy. I didn't have a challenge (even with 6 or 7 letter words), I would have loved to have a challenge to keep me hooked and make me want to replay.
Good submission, good job :)