I hear music that comes out of need, out of grief, sorrow, suffering and out of overcoming these things, as well. That journey to freedom still goes on today. It's an incremental change, the culmination of many events in your own life and the lives of your children and grandchildren.

The question is not... if art is enough to fulfill my life, but if I am true to the path I have set for myself, if I am the best I can be in the things I do. Am I living up to the reasons I became a singer in the first place?

Wherever and whenever I sing, if there is only one spiritual on a program, people will talk about two things afterward, and one of them will be the spiritual. What I bring to this is the best of my classical training - not all of it. I apply what is appropriate.

I bring my classical training - some of it, but not all of it - and also my background and culture, to spirituals. And I try to leave room for that unpredictable factor, where the feeling of the song is allowed to come through. The same ethos can be applied to singing Mozart, or Schubert, or Bach. It's not just about what's on the page.

How many of the original songs survive intact from the slave cabins? Probably not many in their original form. Time has transformed them like light in a prism. What we hope to present is a version of those spirituals, and they speak not just to black Americans, but to people worldwide.

I can't imagine life without singing.

I think for more than half of my career I have refrained from talking to the media.

In spirituals, the talk of heaven and deliverance was code for a better life. 'Crossing the River Jordan' was code, of course, for escaping to freedom.