One of the Echo Nest attributes calculated for every song is ‘speechiness’.  This is an estimate of the amount of spoken word in a particular track.  High values indicate that there’s a good deal of speech in the track, and low values indicate that there is very little speech.  This attribute can be used to help create interesting playlists.  For example,  a music service like Spotify has hundreds of stand-up comedy albums in their collection.  If you wanted to use the Echo Nest API to create a playlist of these routines you could create an artist-description playlist with a call like so:

http://developer.echonest.com/api/v4/playlist/static?api_key=FILDTEOIK2HBORODV&description=comedy&type=artist-description

However, this call wouldn’t generate the playlist that you want. Intermixed with stand-up routines would be comedy musical numbers by Tenacious D, The Lonely Island or “Weird Al”.  That’s where the ‘speechiness’ attribute comes in. We can add a speechiness  filter to our playlist call to give us spoken-word comedy tracks like so:

http://developer.echonest.com/api/v4/playlist/static?api_key=FILDTEOIK2HBORODV&description=comedy&type=artist-description&min_speechiness=.9

It is a pretty effective way to generate comedy playlists.

I made a demo app that shows this called The Comedy Playlister.   It generates a Spotify playlist of comedy routines.

It does a pretty good job of finding comedy.  Now I just need some way of filtering out Larry The Cable Guy.  The app is on line here: The Comedy Playlister.  The source is on github.