Glides (Slides, Scoops) and Drops
Given how music is written, you might expect a singer to simply sing the pitch of a note. That is, of course, exactly what a piano does. But singers often do not do this. (And they will be joined in their "rebellion" by guitarists, saxophonists, violinists, and many other musicians.)
First, the singer can start on a lower pitch and glide up to the correct pitch. In theory, the singer could also start on a higher pitch and glide down, but in practice this is rare to nonexistent. I will call this a glide, but other names for this apparently include scoop and slide.
This is probably the most common "embellishment" in singing -- almost all successful singers make glides.
Having reached the correct pitch, the singer can drop the pitch at the end of the note. Again, in theory the singer could raise the pitch, but in practice that happens rarely if at all. I will call this a drop. I know of no other names for it. I presume people have noticed that drops occur, but I do not recall ever seeing any mention of their existence. They are not as prominent or common as glides.
The glide is sung; the drop can be sung, but usually it is not. Usually, the drop is produced as the note's volume fades away. There is a natural drop in pitch when volume decreases. Of course, if you don't want the drop, you can sustain the pitch, but the natural voice tendency is for the pitch to drop when the volume drops. (Similarly, if you are holding a note and suddenly make a sudden and forceful increase in volume, the pitch will rise.)
To me, the drop is much like the glide, even in function, except that it happens on the end of the note. The "anticipatory drop" is different enough that I would not even include it in this section, except that I don't have any place else to put it.
For example, the first line of "Somewhere Over the Rainbow" ends with the syllable "bow" on the eighth. The next note is the first word of the second line, "Way", It is on the first (or dominant). When I sing the song I like to sometimes drop to the dominant (first) half-way through "bow".
An anticipatory drop, then, is dropping to the pitch of the next note when you are still on the previous note and previous syllable.
A most excellent example occurs in the song "Rainy Days and Mondays", sung by Karen Carpenter. The ending line of the chorus and song is "Rainy days and Mondays always get me down." This is a musical cliche -- a steady drop from the fifth to the dominant. Karen Carpenter adds an anticipatory drop on "me".
The function of the anticipatory drop is unknown. Is it a coincidence that her song and my version of Somewhere Over the Rainbow are both plaintive? Probably, but I don't know.
In the above two examples, there may be more to why an anticipatory drop is added. I am more likely to put in an anticipatory drop when I sing "where", "the", and "bow" before the beat. Karen Carpenter also changes the beat before her anticipatory drop.
NEXT: The Function of Glides and Drops