And I get these compiler errors on the last line:
lime.app.Future<openfl.media.Sound> should be openfl.media.Sound
lime.app.Future<openfl.media.Sound> should be flash.media.Sound
loadSound() doesn’t give you your Sound object immediately. Instead, it starts loading your sound and lets you know as soon as it’s done. Since it returns a Future object, you can register a listener with onComplete().
If you’re including your sound assets normally, then you don’t have to wait. Just replace loadSound() with getSound(), and it’ll return your sound immediately.