system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] In TNG, could any of the bridge crew be speaking another language, and we wouldn't know it, due to the Universal Translator?

I was just wondering this.  Could Picard be speaking French through the whole show?  Could Counsellor Troi be speaking Betazoid or whatever her home planet language might be?  Or, do you think English became the universal language of Earth and diplomacy at that point?
gpt
Standard military protocol would call for all persons onboard to speak a single language while on duty.

This will ensure that, in the event of an issue with the translator, communication will not be hampered.