We don't know (but we can make some educated guesses).
Based on John's voiceover, we're aware that various politicians have accepted the injections along with what appear to be Army test subjects.
John: (voice-over) Some of the VIPs have accepted translator microbes.
A pair of chairs are set up in front of the group. D'Argo sits in one
and an older man is a suit and tie sits in the other. One of Moyas
DRDs, who is sitting on a table, rams it's little hypodermic into the
mans arm while D'Argo speaks Luxan. As the microbes speedily colonize
the mans brain - D'Argos harsh language segues into English.
Under the circumstances, and seeing that the injections have been determined to be both beneficial and benign, it stands to reason to assume that all 500 volunteers would be injected with the translator microbes either before liftoff or shortly after arrival on Moya;
- They'll need to operate the ship, much of which has alien writing on it.
- They'll need to communicate with Pilot, who doesn't speak English
- They may need to communicate with other alien life forms as part of their ongoing voyage of exploration.