I pushed the button too early there - the point I was making was that there are other foreign or dialect words used in English meaning child. But they aren't used specifically or exclusively to refer to the children of particular ethnic groups.

I rather assume, given the etymological roots of pickaninny, in Spanish or Portuguese words that refer to children in general, that this would originally have been how it would have been used in English. (Rather the way I understood it when I was growing up.) Maybe if that commonsense way of using it were restored it would cease to be seen as offensive.