Scat singing is vocal improvisation with wordless syllables, combining improvised melodies, motifs and rhythmic patterns using the voice as an instrument, not unlike a trumpet or saxophone.
Louis Armstrong, Ella Fitzgerald and Sarah Vaughan improvised with intelligence, passion and wit, yet they never lost sight of their lyrics. Jazz ambassador Armstrong, with a voice of gravel and sunshine, is widely known as the cat who first scatted “ooh bop sha bam” after his sheet music hit the studio floor. However, a singer does not have to use scat syllables to phrase like a horn player, as Billie Holiday would often emulate her musical soulmate, Ben Webster, with lyrics.