Maybe because music has beats and rhythms that can make melodies that are usually interpreted subconsciously and make us realize a feeling. Much like how we hear the Jaws's theme song and we immediately connect it with suspense. And for most music also has lyrics, it can also say words or feelings that can relate to many of us. While words are still just words, they don't have such an effect at communicating an idea than music does.
because you might not know how to explain it, but by hearing it said by someone else you might realize what you feelc:)