... or if the meaning of the phrase is *let's communicate peacefully by using different languages*, it would be better to say:
"komunicirajmo mirno jezicima"

If translated literally it sounds awkward and unnatural , though it is just as awkward in English! I suppose that some kind of a row is in question and that you want "normal" communication, "like grown-ups", or something like that? That is why the only acceptable translation is the one I stated, which translated back will be: "let's communicate peacefully, like adults/like men".

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