I'm totally buying the hearing aid thing. That seems the most likely to me.

But I just watched Star Trek: Enterprise episode 109 "Civilization" last night and that totally came to mind. :) Archer and a few others go to a planet that is like Earth in the Middle Ages. They had to make costumes to fit in, but they were walking through the street talking on their communication devices.
So, that could be an alien and when they gathered intelligence to make the costumes, they got the gender stuff wrong. Hehe.