Why, for example, in English is there no way to describe our relationship to a parent's siblings or their relationship to us without specifying gender?
(From Encyclopedia of Genealogy)
That is the only relationship in our family tree that is like that. On the other hand, why is there no way for us to describe our relationship to their children in a way that does specify gender? These are collective decisions made over generations. Language shapes discourse, inserts itself into the conversation, creates ambiguity all on its own.
"All that glitters is not gold."
How much of what glitters is gold? When we use that sentence we mean some of what glitters is gold and some is not.
"All who lie are not trustworthy."
How many liars are not trustworthy? If we were to say it that way, we would mean that all of them were trustworthy. Why is it some in one and all in the other? What about,
"All of the people in the room were not represented."
Is this a golden clause or an untrustworthy one? I recall from my linguistics class that in the US, the tendency to interpret this clause one way or the other or as ambiguous is affected by what part of the country we are from. Regardless of that effect, it is likely that we could use a statement like this one unaware that it is a problem. Every conversation takes place in the context of our cultural history, even if we are unaware of it. All our efforts to be accurate will not work.