I am pretty sure i have read somewhere that music stimulates your brain and make you relax while sleeping, depending on type of music i would assume. Also you are supposed to learn more quickly while you are sleeping so put on your language course while sleeping by using this great gadget, the Sounds Asleep Pillow.
The Sound Asleep Pillow, or ipod pillow as it has also been called, is basically an ergonomically designed, contour molded memory foam pillow that has a speaker burried deep inside the pillow. No more waking up with sore ears from falling asleep with the earbuds in your ears, or keeping your partner/flatmate/neighbour awake with your stereo blasting while you are asleep.
The Sound Asleep Pillow is available from IWantOneOfThose.com for only £29.99.