I have an English version of a female singer that does the song "Free"
written by Stevie Wonder.  I believe it is Khadja Nin, but I can only
find her singing it in her Native tongue (not English).  However,
perhaps she did do it in English on some album, although I certainly
can't find it.  So, my questions are these - did she do an English
version and if not, is there another female singer that does the song
(in English) "Free" by Stevie Wonder ?

Khadja Nin recorded a CD single of "Free" that was released in
Germany. I have not been able to learn whether this was sung in
English or Swahili.

http://www.musicstack.com/item.cgi?item=13433110

The Israeli singer Dana International has done a cover version of the
song, but Dana International does not sound very much like Khadja Nin.