You can sing it in your head, but not out loud. Why?

My hypothesis is that singing in your head just involves the brain replaying a sound that it's already processed, but actually vocalising sounds relies on muscle memory, so if you haven't had practice forming those words in the past then you probably won't be able to do it with ease or any degree of precision in the future. less

I'm huge into foreign music, mostly Korean, Japanese, and some Chinese.

I have songs that I've heard a million times over. I can sing them perfectly in my head even though they are in a another language, but when it comes to singing it out loud that's another story. It's like my mouth forgets how to work.

I've be curious to why is that?

I've searched all over the internet and seem to can't find an answer.

Do you guys know? less

My hypothesis is that singing in your head just involves the brain replaying a sound that it's already processed, but actually vocalising sounds relies on muscle memory, so if you haven't had practice forming those words in the past then you probably won't be able to do it with ease or any degree of precision in the future. less