I keep thinking the book is by Hannah Howell but I've been unable to find it so I'm not positive.
Here are the few things I remember about the book...
1. Set in Scotland 2. Hero and others are held captive by enemy for years 3. Hero tortured while being held 4. Hero is eventually rescued by brothers but by than is mute and savage from the years of torture 5. Heroine met hero at the place where hero was being held, I think the man holding the hero is trying to get the heroine marry him
That's about all I remember. Any suggestions on what book this could be?