In the quest Urianger says "He spoke but few words, carefully chosen, their tone and timber alone threatening to rend my heart in twain. Challenging his desire to remain may allow us to alter the island upon which we stand."

When discussing the quality of someones voice the spelling Timbre (pronounced tam-ber) is used on both sides of the pond. I believe it was mistakenly localized to timber which makes me think of trees. By the context of discussing tone and how one is speaking I believe timbre should the right spelling.

Timbre is defined as "the character or quality of a musical sound or voice as distinct from its pitch and intensity."