Until today ...
No matter what I tried, I had a recurring hiccup plague my existence today. The longest bout lasted for a little over an hour and made it so, much to my students' entertainment, I had a high pitched squeak that would occasionally escape whenever I talked. Even more frustrating was the fact that the hiccups then attacked me at several more points during the day.
I don't know if my control of my diaphragm is less precise, or my "growl" is just less effective, but it led to a rather annoying day. The good news is that I have not had another bout for the past several hours. I just hope they stay away.