I like to watch lectures on high speed (usually between 1.5x and 2x) with VLC. The limiting factor is often the rate at which the speech becomes unintelligibly clipped/choppy. Is there software that smooths out audio of human language in a way that allows for higher playback speed?
To be clear: I'm looking for something that intelligently modifies the audio beyond just a uniform speed up, e.g. compressing the pauses between words while stretching out the words themselves, or making consonant sounds "crisper", etc.
(I am interested in any operating system, but ideally this would be for OSX. Even more ideal would be a VLC plugin.)