This indicates if the soundtrack is in stock. By Vocal track I mean that the majority of the track is sung. By Dialogue track I mean that the majority of the track is spoken dialogue, whether it be one person or multiple persons. By background music I mean that the track comes straight out of a series. Background music, as its name suggests, is usually played in the background of a scene, and usually doesn't have any vocals.
Any vocals are usually in the form of chants.
By instrumental I mean that the track includes no vocals of any sort, and is, well, only instrumental. I made instrumental and BGM tracks one number because most BGM tracks are instrumental anyways. The only difference is that BGM tracks come straight from a series while some, the ones I am considering instrumental tracks, do not. This is a small picture of the CD's cover booklet. You can click on it to bring up a full size scan of the cover.