When the song or "sound" becomes something you believe deserves to be called music. It's only music if it feels right in your heart, that's what it's all about.
I belive it started when somebody accidentally whistled, and then tried to control the notes, and mimic bird calls, then wood winds followed. Or maybe drums came first, again by someone thumping on a...
Very likely from rhythm and voice. Nature is full of rhythms, from the beat of a heart to the turn of the seasons, and rhythmic beating and clapping are found in very primitive music. Change the...