@kacey To be honest, it all started to go wrong when those crazy kids stopped using proper Anglo-Saxon dual pronouns....
But does “us two” include the speaker and the person being addressed, or the speaker and one other who is not the person being addressed??
We have this in English, but I have a sneaking suspicion that there are languages where there are two "we" pronouns, one of reach of those.
I'm actually a thouist myself - I spend way too much time saying "you - I mean all of you, not just you..." and other stuff that adds meaning to the vague "you" that we currently use!
Doesn’t the dual persist in English a tiny little bit? Isn’t “oxen” originally a dual? And although “shoon” is archaic, I think even that persists as a brand name for a shoe shop.
@donaghy @kacey Not sure about oxen. Could just be similar plural suffix to "children". English plurals are a mess because of mixed origins, loss of older endings, generalising one example to others, simplification of using "-s" as suffix etc. Some Germanic plurals based on vowel change (umlaut) e.g. goose/geese or mouse/mice. Sometimes no suffix e.g. fish, sheep.
Mind you, Welsh plurals are even worse - different suffixes, umlaut, "singulative" endings etc. Great fun!