Voice quality formula:
Voice quality = vocal tract configuration + laryngeal anatomy + learned component
Here are some voice qualities:
1) aphonic - no sound or a whisper
2) biphonic - two independent pitches
3) bleat or flutter - sounds like a lamb's cry
4) breathy - sound of air is apparent
5) covered - muffled sound
6) creaky - sounds like two hard surfaces rubbing against each other
7) diplophonic - pitch supplemented with another pitch one octave lower, roughness usually apparent
8) glottalized - clicking noise heard during voicing
9) hoarse or raspy - harsh, grating sound
10) honky or nasal - excessive nasality