I have another creative bubble I want to send here. It's just out of curiosity. I know that in a military setting (sci-fi in this instance), the characters call each other by title and name. The aliens do it too (at least in some of the sci-fi shows I've seen.) But what if an alien refused? Does it really matter much if an alien doesn't want to call the commanding officer by his/her title? I just figured that it kinda does, as you're working for someone of authority who just happens to be a different race. By not calling the person by the title, you're showing disrespect.
If it's the alien not wanting to properly address the alien commander, it's your story and your type of alien - invent the consequenes for if this happens Alien not addressing human commander - are they on the same team, or enemies? if they're enemies, it doesn't matter, they're not going to use proper titles anyway. If they're teammates, it'd depend on the reason...can the alien not pronounce it, or just doing it out of disrespect? what's the personality of the commander (I'm assuming Helen Chert) - how would she handle this? This would be a decent question if it was a human not respecting a human commander, but because it's aliens, YOU decide...there's lots more room for creativity and less realism-based constraints.
Well, Helen does demand respect from humans and aliens, even those who's culture is "women=not strong". If one of them showed her disrespect and she knew it, she'd threaten to eject their sorry ass out of the airlock and leave them without a second's thought. Yet a Devonian companion of Helen's, Kenthew, just calls her "Miss Chert". While I don't know why he does this, I just know that Helen accepts it and lets him call her that instead of "Captain Chert". It's even more bizarre because he does come from a culture that celebrates the men more than the women. I'd blame translators as the excuse, but then how would you explain an alien meeting a Frenchman, a German, or a Japanese man? Would we then hear conversations in Japanese (with English subtitles)?
I think the aliens decided that having a quick English crash course might be useful to do whatever they want to do with Earth. Anyway, from what you've said so far, this "Captain Chert" seems heavy on respect. I'd guess she would say something that sounds threatening to hammer in the fact that you must address her as Captain to the alien, without provoking war. So maybe: "It's Captain Chert, not Chert, soldier."
Because they sent Mork here to study our ways and language and they have language-reading technology. Well, he probably does this because you wrote him that way. Otherwise, why would he say "Miss" instead of "Captain"? That makes very little sense, really. I mean it. That makes absolutely no sense. What's the difference? Are they especially close? If so, why doesn't he just refer to her as "Chert" or "Helen" depending on what sounds his voice box can make? Well, obviously not if they were French or German. But yes, I should hope we'd get it in their language. That'd be nice and appropriate. Subtitles: optional.
This is basically a respect issue. grand scale; do the aliens respect the humans(enemy or not) using proper titles shows respect. Are the aliens trying to annoy the humans. If they are trying to incite anger, using improper titles would fit. Do the aliens understand which titles humans view as being most important. If aliens place high value on a woman, using a feminine title could be higher then military rank in thier view. Are the aliens trying to negotiate a treaty or deal. Using proper titles would benefit them. Individual scale: Does the alien respect the person? purposely trying to annoy her? Use the wrong title out of ignorance? Enemy military can use proper titles if they know them and do not disrespect the person. Punishment: can be severe depending on the culture of your military.