The Unanswered Question - a series of six Norton Lectures given at Harvard University by Leonard Bernstein in 1973.
Bernstein successfully relates the historical evolution of music with linguistics in this fascinating lecture series. Mostly advanced level discussions of music; may be slightly difficult to follow. Sticking with the lectures, however, is time well spent.
Lectures in order:
I. Musical Phonology (shown above)
14/50 of my favourite John William Waterhouse art:
Consulting the Oracle (1884)