Well, doesn't music kind of have to be a language? Because, for example, we speak and write in english and I am writing down words right now. To be able to read the words I wrote, I have to know how to read and write in english, right? And we read and write down music, so doesn't that make it a language??
And if this is true, I can totally see why people would call it a universal language. Because we mostly speak english in the US and...japanese in Japan. But if anyone in the world wanted to read music, wouldn't they would be able to??