[legacynl]

Learning by listening to something during your sleep doesn't work. Brains go into a sort of maintenance mode during sleep, and it's not possible for your brain to sleep and interpret & comprehend sensory input at the same time.

Most likely the noise will have a negative effect on the length and quality of your sleep, which does have a proven negative effect on memory.

So it's probably better for you to learn while your awake and just sleep at night.

[AlwaysRock]

It doesnt work but placebo is strong. If someone thinks it is working, while also learning in other ways, then its likely working.

[xapata]

The placebo effect is so strong that it even works if you know you're taking a placebo. Brains are amazing!

[passion__desire]

Whether you are fluent in a language or not is decided by others i.e. society and not you. How is placebo effect relevant here?