I first became acquainted with Doug’s work while working in Ghana in the late 1980s, when a colleague loaned me a copy of Doug’s MIT dissertation Tone in Lexical Phonology (which, if I remember correctly, he had purchased in hard copy directly from the MIT library!). I was in the fairly early stages of work on a tone language (Nawuri) and read it with great interest. Shortly after that I became acquainted with Doug’s early work on tongue root harmony and especially his classic 1989 paper with Diana Archangeli on Yoruba vowel harmony, which was a tremendous impetus to my own thinking and research as it has been for many other people. In my opinion, that study is one of the most insightful and well-reasoned analytical treatments of a tongue root harmony system that has ever been produced. To this day, it deserves a place on anyone’s short list of essential readings on tongue root harmony.
Across several decades of change in the general currents of phonological theory, Doug’s research has remained influential and highly relevant. I have appreciated reading his work over the years and have always found it clear, though-provoking and well-reasoned—the kind of work one really looks forward to reading. I have also been consistently impressed by the level of detail and careful and thorough presentation of language data found in Doug’s research articles.
All the best wishes, Doug, for a very happy and health retirement!