Songs without words

I was interested to read an article by Frank J. Oteri in New Music Box today that resonated with me. He complains that increasingly all music is being described as ‘songs’. I’m grateful to know that I’m not the only one who calls a song a song, and an instrumental piece, a piece or composition. It’s only since coming to the US in fact, that this has been an issue at all. When I began to teach piano, I was astonished when some of my students referred to their pieces as songs. I’d love to know how this started- any ideas?