There are two nice recordings of children singing classical music which I play for my little son and we both enjoy them:
(https://images-na.ssl-images-amazon.com/images/I/51Og12HxINL.jpg)
There are several, great children songs in this Hindemith box:
(https://m.media-amazon.com/images/I/51P0d8lX0vL._AC_UL436_.jpg)
Can anyone recommend more recordings? Singing language doesn't really matter.
Nobody have children here?
A nice, short example of Henze's greatness, this short little interlude:
https://youtu.be/xinxLXIE2Ig?t=1492