How do I know if it's pronounced "le" or "yue"?

I've seen it as "le" in 快乐 , but also as "yue" in 音乐.

So I was wondering if there's some kind of rule to it? There's a girl in my class this hanzi on her pencilcase and she asked me what the pronounciation was and I wasn't sure which one it was >.<

Thanks

快乐

They are 2 different words/characters with different pronunciation. 音乐 is music and 快乐is happiness.

the answer is both

I know this, I'm asking if there's a special rule to know when it's "yue" or "le"; or can they only be combined with 快 and 音? Can't 乐 be used with other hanzi? If it can, how do I know which is the correct pronounciation?

Only certain sets of words work, you just need to know off by heart, Chinese is weird like that.

However, yue is often associated with sound/music, le is with emotion/joy.

乐谱 for example is music sheet (yue), 娱乐 is leisure (le).

ok, thanks!

weird!