It only took 4 years, but I finally remembered the title of that historical YA novel I read back in 6th grade.
Here's a review. I was close on several details:
The first half of the book is about Quick Eagle, the son of a respected Miami chieftain, and the person who seemed most likely to qualify in the future to assume leadership. The second half deals with John Cutchen, the name Quick Eagle took after he discovered in horror that he was really white and had been kidnapped as a baby. This is a very personal study of his agony which lasted for a two year stretch right after his attainment of manhood. His complete loyalty to his tribe and its traditions are made very clear and are particularly signified by the very close relationship between Quick Eagle and his adored father. But he could not reconcile the fact of his tainted blood with life as an Indian so he severed himself from the tribe and went to live in solitary among Americans. After he learned who his true father was he agreed to be a translator for Clark's expedition. His suffering came from being an outcast of two completely opposing ways of life, neither of which was per se right or wrong and his personal reconciliation eventually came when he recognized himself as a man rather than as an Indian or a white person and when he realized that he could function as a ""bridge,"" a trader and a go-between for the two sides. It's an excellent portrayal of human relations, and one which will suit the idealism of teenagers.
It's only 4 pm on Wednesday, but I feel like I've accomplished a week's work.
(Don't keep me waiting so long next time, Memory, because I WILL get all Javert on your elusive ass.)