Many languages in the world distinguish between plural and dual (and sometimes trial) pronouns (for instance, “you” specifically addressing many, two, or three people).
In Matt. 20:22 (“You do not know what you are asking…” in one English translation) it is left open whether “you” refers to James and John or James and John and their mother (who had asked the questions preceding Jesus’s answers).
While one Fijian translation uses a trial and the Wantoat uses a plural (both indicating that the mother is included), the Bislama translators (in the Nyutesteman long Bislama of 1980) uses a dual (indicating that the mother is not included).
One of the translators explains: “Here, because of differences between this Matthew passage and the parallel passage which begins at Mark 10:35, the translator must enter into the issues of the so-called “Synoptic Problem” when deciding how many people Jesus is addressing. I suggest the following guidelines for making a decision here and in the passage considered below: a single real historical event is recounted by both Mark and Matthew, both without error, although each with their own selection of material and emphasis. So what do we make of the fact that Matthew has James and John’s mother asking the question, whereas Mark does not mention her at all, having the two men themselves ask it? We conclude that she must have been there, since Matthew says she was; but she was not important in Mark’s eyes, and so he abbreviates her out of his account. Now the answer Jesus gave to the question is identical in the Greek text of the two gospels; and it must have had only one intention, even though as it stands in Greek, it is ambiguous as to dual or trial reference. I suggest that although the mother asked the question, Jesus either perceived that she was merely a ‘front’ for the two men, or else his primary interest was in them anyway, and so he bypasses the mother and makes his answer directly to them. This is certainly the way Mark saw the situation.”
Source: Ross McKerras in Notes on Translation 2/1 1988, p. 53-56.