QuickerTime
A while ago I read, somewhere, about how you could speed up sound by a certain factor and still be able to hear what was said. The context was busy executives using specialized video players to quickly get updated on the news. But I can’t remember by what factor they increased the playback speed.
Anyway, I had the idea that perhaps you could use AppleScript to change the playback speed in QuickTime. And sure enough, you can do a
tell app "QuickTime Player" to set the rate of movie 1 to 1.8
which is a good average speed. I tried it on Brian Greene’s The Elegant Universe TV series, and it seems to work for all his interviewees. If it weren’t for some of the faster talking ones, a factor of 2.0 could easily be used. (Of course it works on both movies and sound files.)