Depending on how you want to use it, you might be better off with one of the small recorders that offers this slow-down playback.
There are a few available that are large-pocket-size. Record (via built-in mike) from any source you can find, and then listen to short sections at about 2 or 3 to 1 change in speed.
My understanding is that they use internal RAM to "snatch" and digitize up to 30 seconds or so of the original audio, and then you just flip a switch to the "slow" position to play back. The ones I've seen generally loop short sections easily, so you can study them.
Sorry I don't have a brand name or contact info at hand, but if there is an interest - and if the thread stays alive long enough - I'll see if one of the guys I know that has tried them can provide some dope on them. Unfortunately, my best contact on this is a long-haul trucker - so I never know when I'll see him next.