Some voices can be characterized as breathy. The vocal folds vibrate to generate voicing and breath noise simultaneously. Breathiness is a characteristic of many female voices, but it is also common under certain circumstances for male voices.
The range of the Breathiness (br) option is from 0 dB (no breathiness) to 70 dB (strong breathiness). By experimenting, you can learn what intermediate values sound like. For example, to turn Paul into a breathy, whispering speaker, use the following command:
[:np][:dv br 55 gv 56] Do I sound more like Dennis now?
This voice is not as loud as the others because of the simultaneous decrease in the gain of voicing, gv, but it is intelligible and human sounding.