A cross between
vocal singing and
dramatic declaration.
This effect was supposedly first used by
Schoenberg in his 1912 chamber piece,
Pierrot Lunaire.
It has often been seen in chamber and choral composition since then.
Whispering,
laughing, whistling and
animal emulation would all fall under this category.
John Cage's "
Dining Room Music" is a good example of this practise in use.