I found someone else online who found the answer. Here's a great way to create an automator application that will do it. NOTE: use one of the commenter's suggestions to avoid leaving AIFFs lying about.
I did this to a 9 hour novel and listened to it with Alex. Once getting used to the cadence, it was great.
Wow, so simple! This is the first time I've even opened Automator in 9 months since I switched to Mac, and I'm surprised how easy it was to use. Thanks, now I've got a way to spit out lyrics for this electro track I've been working on