English terminology isn't wrong, Cap'n, it's just different form Irish usage. The two-row or three-variety of diatonic box is almost always referred to as a "melodeon" in England, so that's its name.

There is an instrument that has a full set of accordion-style bases combined with a melodeon right hand keyboard, and John Kirkpatrick refers to this as a "button accordion" to distinguish it from the melodeons and the piano accordion that he also plays.

But you're right about the push-pull making it difficult for some singers by interfering with their breathing. I can sing while playing, but I can't speak, for some weird reason to do with breathing.

Marje