Translation:We are going to have a coffee together.
ok, now I'm a bit confused. I'm trying very hard to understand and absorb all the subtleties of the language and thought I had this one figured out per a previous discussion thread. I understood from an earlier comment on another post that "on" meaning "we" was closer in meaning to the English "one" rather than to the English "we," though we/you/one are used when speaking in generalities, such as "one could get there by bus or train," "we could get there by bus or train," and "you can get there by bus or train." I thought that when speaking about "we" specifically, such as here, you have to use "nous."
Everything you said is correct! The only thing is, french natives prefer to use in their day-to-day informal language "on" rather than "nous", because it's simpler and the conjugation is also easier. Check http://www.assistancescolaire.com/eleve/4e/francais/reviser-une-notion/utiliser-le-pronom-indefini-on-4fpr33 if you need more info.
I discussed this with my wife (who is a native speaker of Quebecoise French, and also has a university degree in French language and literature) and she thinks that the speaking/writing difference is pretty much artificial. It's a difference between casual speech and formal speech, and the "speaking vs writing" issue comes up because until very recently (within the last two decades) most people didn't do very much casual or informal writing, before the Internet and texting and so forth. So you could say, "Yes, that's right, 'on' is for speech and 'nous' is for writing," because most people just didn't write all that much in a very casual, informal way. You wrote for business, and for school; you wrote letters, but most of us still write more formally in a letter--even if we're just writing to Grandma--than we do on, say, Facebook.
So you would use "on" in conversation, and on Facebook, and in texts (where I frequently see it abbreviated to "n"), and in a quick note to your friend or your spouse--but you would use "nous" not only in things like work reports or school papers, but when you're making an oral presentation or giving a speech (unless you're specifically trying to sound casual and "folksy," like political campaign speeches often do).
I tend to put things like message boards and forum posts in the "casual/informal" category myself--I have to try to be clearer than I would in a text to my wife, because she actually knows me, can fill in a lot of the gaps through our shared experiences, etc., but I'm still not writing like I did in my thesis.
Depending on the language and the region, the answer may vary.
In French, saying "un café" means they're going to have only one coffee, whereas, "du café" means some, which is unspecified amount, could be one; could be more; could be less.
In English, it depends on whichever is commoner in a region.
Some people say "a coffee" and other would say "coffee" when they both mean the same thing.
The English translation here uses 'have' because that's the common English idiom. But the most commonly used French form is prendre - to take. It's also what is used for ordering food and drink. "Je prends un café" -"I take a coffee" is what you use when you want to order a coffee. So while 'On va avoir un café ensemble' does literally translate to we are going to have a coffee together, it is not on the whole the idiom used in French speaking countries. So prendre is the verb that should be used.
This is a mistake that francophones sometimes make. A francophone will not use "avoir" in the sense of "to consume" something. But "prendre" (which learners fixate on as "take") means "to have" in the sense of to eat/drink/consume something (food, medicine, etc). So best get used to the idea that "prendre" has different meanings that are influenced by the context.
- Je prends un café = I'm having a coffee
- Il prend ce livre-là = he is taking that book
- J'ai un café = I have a coffee (it's right here in front of me) does not mean I'm drinking it.
We're having a coffee together is also present tense, so it's not close enough. And We will/We'll is closer to Nous prendrons un café ensemble or on prendra un café ensemble. We are going to have is a more direct translation as well as being a natural English phrase with no ambiguity about it being in the future.
There is nothing capricious about it. It is a matter of context. Please visit this link and look at all the possible meanings of "prendre". In the context of food, it means "to have" (to eat, drink, consume). In the context of medicine, it means "take". https://www.larousse.fr/dictionnaires/francais-anglais/prendre/62856
What's wrong with "We are going to have a coffee"? "Together" was not specified in French why should it be specified in English?