For those who might be interested, I have set up a VoiceMacro profile for FreeSpace (attached).
Once the comms panel is opened (C or equivalent), you can navigate the menu by speaking digits (Zero to Nine) or using common names and commands, e.g. "Beta" or "Form on my wing". Specific ships have to be designated via digits. It's also recommended to pay attention to wing names in the command menu - "Beta" is predefined to press "2", so if Alpha's gone and Beta is now assigned to digit "1", you won't be calling Beta by speaking its name.
A synthesized voice immediately repeats your commands after you've entered them to confirm that your command is correctly interpreted. I've played through the Great War campaign with it and it works quite well.
To avoid untimely button pressing, I also added "open channel" and "close channel" commands. Other commands will be executed only if the comms channel has been opened. I usually leave the channel opened throughout a mission, but if the synthesized voice is too keen to recognize your grunts, you can close it at any time.
Set up commands:
Zero to Nine
Alpha to Epsilon
Requesting support (=rearm/repair)
Destroy my target
Disable my target
Disarm my target
Protect my target
Ignore my target
Form on my wing
Don't forget to train Speech recognition on Windows before using it.