'True for us'

I'm sure I've said this before, but I was pressed very specifically on this question in a recent discussion and I think the answer is worth putting succinctly:

Can't we only say that "We can talk" is true for us, rather than in general?

If a statement must be true in any language game that we can play, then 'true for us' is 'true in general'. This is because 'true for us' suggests 'false for someone else' - someone playing a game we cannot play presumably. The trouble with this is that if it's a game we cannot play, then it's a game we can't translate - so we we don't know whether we're dealing with a language at all. This is obviously Davidson's line, and I think he's right. Also from Davidson, we can see that a translation hypothesis which rendered the belief system of the subjects being translated absurd or false would (principle of charity) be rejected. (If we did not reject translation hypotheses of this kind, we would have no grounds for rejecting any translation hypotheses - if we allow that people talk nonsense, we can allow them to 'say' anything at all.) Since 'we can talk' must be true for us, a translation hypothesis rendering a 'foreign' expression as 'we cannot talk' would have to be rejected.

If it isn't 'true for us' then we can't intelligibly hypothesise that it is true for someone else.