Translation:We depart now!
Yes, it can be used that way. You're making a suggestion by projecting it into a statement. You could do this in English the same way: "What should we do?" "We'll leave now." There's no need to add a Ha' to get the "let's," and the concept of going somewhere is already embedded in the meaning of mej.
Yes. Grammatically speaking it's a simple indicative statement, but it could be used as a suggestion, an order, or even a question given the right circumstances.
Power Klingon, for example, translates Ha'! DaH matlhutlh as Let's go get a drink, even though it is literally Let's go! Now we drink.
Do not expect Duolingo to accept these sorts of translations, though.
Klingons don't have set greetings and we don't want to encourage people to think of this as the Klingon phrase for "goodbye". In fact I would suggest that Klingons are more likely to say, Qapla' upon parting. However, the most typical way for a Klingon to part is just to leave. If there is some information that they have to impart before leaving, then they will say whatever it is they have to say. If it is important for someone to know that they are no longer there (for instance if the number of people present makes a difference), then they might say a sentence like the one in this exercise.
Right, the reasons you would say mamej are usually not the same reasons you would say goodbye. You would only say mamej if the party you're saying it to didn't already know you were leaving; you usually say goodbye to someone who already knows you're going to leave. They really don't mean the same thing at all.
Fair enough! I was aware that greetings for their own sake are not really encouraged for the reasons you mentioned. But I have run across more than once where someone (a better speaker than I) cited "DaH jImej" as basically the nearest thing to it, so I assumed it would be included as such in DL's lessons. Not as a primary translation obviously, but as one possible interpretation of the phrase. Either way, thanks for taking the time to reply!
There are some speakers who expend a lot of energy finding grammatically correct Klingon expressions that mirror things humans say in greeting one another: qaleghneS; tugh maghomqa'neS; choQaHta'mo' jIQuch. They present them to me with an expression of triumph, as though they have fixed Klingon, overcome its limitations. Just because you can express the semantic meaning of an English expression in Klingon doesn't mean that you should, or that it's an appropriate thing to say. One of the hardest things about speaking Klingon (tied with learning that prefix table) is not saying anything in situations where your own culture requires you to do so.
Culture is a huge part of any language, even artificially constructed ones. Klingon was not created for either efficiency or adaptability. If that's what someone is looking for in a language, there are other great languages for that. What many of us love about Klingon is how the grammar and cultural norms are so different from our own and the language challenges us to break our assumptions and be creative in our solutions. Because of that, many of us are quite serious in holding fast to those artificial limitations. Like many games played for pure entertainment, the rules are an important part of what make the game fun. It's no fun playing with someone who wants to ignore the rules.
That being said, there is a place and time for strictness or for laxity. In a classroom situation, like here on Duolingo, expect us to be very strict on the rules of the game. We want to teach you the right way. If you decide to vary the rules later, that's your choice. Don't be surprised if it causes confusion, but sometimes you have to test the rules to find the limits.
In a casual in-person conversation most Klingon speakers will be very flexible and forgiving. In a situation like that, maintaining the flow of the conversation is paramount and as long as the intent is understood, questionable choices will often be ignored.
The written medium is yet again something different. Though successful communication is often the primary goal in a written medium, the fact that words sit there and do not leave provides us opportunity to complate the choices made and to have multiple responses to the material. Thus we might respond to the content and/or we might respond to the form. It can be very helpful for beginners to be corrected in these situations. It can also be helpful for beginners to see the corrections made on intermediate speakers. Of course, it can be quite frustrating to get multiple corrections of form and no responses to the content, but that is the weakness of the written form. Unfortunately so many speakers are spread so far from others that live conversations with experienced speakers can be difficult to impossible. We are hoping that this course is creating opportunities to begin to change that.