Sorry to bump up the thread... the latest version has a partial solution to this.
The /xshutup commmand stops and clears the buffer so that anything your contact just said won't be dictated.
http://rdmsoft.com/rdmspeech_installer.exe
A proper mute command is a good idea though, I'll look at it tomorrow.
}{}{}{}{
"right curly bracket, left curly bracket, right curly bracket, left curly bracket, right curly bracket, left curly bracket, right curly bracket, left curly bracket."
edit: Added /xspeechmute -
http://rdmsoft.com/rdmspeech_installer.exe - 26KB
