Bill Frisell's technique differs from mainstream jazz in that it is entirely dependent on the melody, not the chord structure.
Interviewer: Your approach to melody seems unique in that you break it down piece by piece until you are dissecting the elements of sound within the context of melody. Can you explain that process?
Frisell: When I first started getting into jazz, I studied what was going on with the music theoretically and would look at things more in a mathematical way. I would look at the chords and learn what the chord tones were, what the scales were. But somewhere along the way, I tried to understand all the inner workings of the melody. If the melody isn't there, then it really doesn't mean anything. It's also where it gets harder to explain. With every song, I'm trying to internalize the melody so strong that that's the backbone for everything that I am playing no matter how abstract it becomes. Sometimes I'll just play the melody over and over again and try to vary it slightly. It's really coming from that, like trying to make the melody the thing that's generating all the variations rather than some kind of theoretical mathematical approach.
Interviewer: Could you explain what you mean by internalizing the melody?
Frisell: It's playing and hearing the melody and not playing anything but the melody until it starts going on inside your body, even without thinking about it. But the older I get, the longer it seems to take to learn new things and get it to the point where it's really deep down in there somehow."
Source: All About Jazz Forum, Bill Frisell on Improvisation and Internalizing the Melody