The deliberate choice of scat syllables also is a key element in vocal jazz improvisation. Syllable choice influences the pitch articulation, coloration, and resonance of the performance. Syllable choice also differentiated jazz singers’ personal styles: Betty Carter was inclined to use sounds like “louie-ooie-la-la-la” (soft-tongued sounds or liquids) while Sarah Vaughan would prefer “shoo-doo-shoo-bee-ooo-bee” (fricatives, plosives, and open vowels).