i have been learning to use less commas as the english language changes... i'm happy to find them here!
There are, technically, two sentences. Main 'we do not know" and a side one, that depends on the main one and would not make sense without it but is a side sentence. The main sentence makes sense alone. We do not know. We do not say what it is we do not know but we know we do not know. Side sentences are separated by commas.
Thanks. From your answer I can conclude that Czech rules for using commas are stricter than Serbian. For many types of dependent clauses we do not have to use comma to separate them from the main clause. "Ne znamo da li smo braća."
The simplest rule for Czech could sound "Separate all verbs by commas".
I suspect some orthotypographic influence from German over the centuries for this "comma rule". I don't think it's a very widespread feature among all the world's languages to have a compulsory comma boundary between clauses.
I think Czech language is quite "liberal" in question of orthography. You should try Romanian :) https://ro.wikisource.org/wiki/Povestea_lui_Harap-Alb
I think Fallengone would prefer “if” instead of “whether,” and intended to say “than”, not “then.”
There is quite a number of web pages on “if vs whether.” They mainly quote examples where “whether” is preferrable or even required, for instance after a preposition or before an infinitive. “If” seems to be required instead of “whether” only to introduce a condition, which is not the case here.
So I do not understand either.
i very rarely hear anyone in english say "whether" without "..or not" tacked on. to me this sentence sounds strange in english and i think it would be said with "if," i agree. if it was "whether we are brothers or not," then it would sound right.
I'm native AmE and I also use, and often hear, "whether" used both with and without "or not" tacked on. There are (and have been) acceptable translations using both options. I've added an additional "if" version.