Sorry speech recognition feature (Voice Command) 's documents
are only available in Japanese...

Because Japanese version of ViaVoice must be installed on your
system and voice commands must be Japanese...
(You may need Japanese IME(Input Method Editor) to specify pronunciations)

If you can speak Japanese and you have Japanese ViaVoice,
read the "Voice_ja.txt" file in this directory.
Some usage are written in it.

But with no guarantee!!!
Use this feature at your own risk!!!