While we're proposing alternatives to the recorder, I'd add the harmonica as an accessible instrument. It depends on the kind of music one wants to play, but th

While we're proposing alternatives to the recorder, I'd add the harmonica as an accessible instrument. It depends on the kind of music one wants to play, but the harmonica is easy enough to start playing for a child, and the range of expressivity has room for expertise to develop (chromatic harmonicas are difficult but can produce sweet and exotic scales..).