[Johnbalaya]

Someone had mentioned before that greek was spoken by the Roman soldiers in that area at the time, but the Legionnaires assigned to accompany and guard the Roman governor spoke Latin
(speaking greek was supposedly distasteful because it was "barbaric").

[Natural Law]

All Roman aristocracy was educated in Greek. Furthermore, many professional soldiers were of Greek origin so it is entirely possible that Greek was casually spoken, but all official communications was Latin.

[RobbyS]

I think these soldiers were from Gaul and that they were about as likely to speak local languages as are American soldiers in Japan.