speak - none, normal or spell-out
pause-before, pause-after - time or percentage
cue-before, cue-after, play-during - audio sample
azimuth, elevation - directional separation of sounds
pitch, speech-rate, volume
voice-family - names voice font
stress - level of inflection
richness - not clear what this is
speak-punctuation - whether to speak ; ( ) . ,
speak-numeral - speak numbers as digits or words