KT Tunstall's strange relationship with music has been explained: she didn't listen to it as a child:
"My parents don't listen to music. They're real outdoors types so we just went camping. And my younger brother is profoundly deaf so it was very unhelpful to have music on in the house."
While we can see that extraneous background noise would be awkward for someone trying to understand conversation, surely she didn't spend her entire childhood in the same room as her brother? And since when did 'going camping' preclude you from listening to music as well? "Put that mouth-organ down, Katie, I intend to fashion it into a rudimentary tent-peg."
It explains why she makes music as if it was a second language - not, of itself, a bad thing; indeed, the passion of a late convert could have made for some interesting, sharp-edged stuff. It hasn't, of course, but it might have done.