Step 1. To save time, split the MP3 file into parts
This is a screenshot from a freeware Macintosh program that will split MP3 files at the silences without needing to re-encode the MP3, so you won't lose quality.
I assume that there must be a similar program available for Windows. (Someone send me a link to a freeware program, and I'll add it here.) AudioSlicer (Mac Freeware)
Step 2. Listen to it all one time, if you like, or jump directly to step 3.
I've made notes in the "Artist" tag, so you can see what the content of each part is.
Step 3. Delete the parts we usually fast-foward through, then listen to it all one or two times.
This will usually save you a lot of time and you can focus on the content of the lesson.
Step 4. Delete all except the 3 versions of the dialog and then listen to these files a few times.
Notice how I duplicated the file entries in the playlist, so you listen to the dialog multiple times.
Step 5. Archive the files from step 3 or 4, then listen to them again in the future.
If you think it would be useful to save the in-depth discussion about the dialog (along with the laughing and chatting), then save all files in step 3, otherwise, just save the 3 files from step 4.
Dialog at normal speed.
Dialog at slow speed.
Dialog with English.
Note that if you don't do step 4 and 5, then it probably isn't worth your time to do step 1.