Music is a universal language, but the German that Bach uses in his sacred music is not. "When God Sang German" explains the etymologies and precise meanings of words like Gott (God), Mutterleib ('womb'), Schuld (debt, guilt), Glauben (faith, believe), and Gnade (mercy, grace). The Introduction traces the history of German, with particular regard to language in music and to Luther's importance to Bach. The thirty main chapters are each built on a...