Perfect tense question
Tá a hata caillte ag Seán.
Does this mean that Seán has lost someone's hat, or that he has lost his own hat? Or would that be something like tá hata Seán caillte aige or tá a hata fein caillte ag Seán?
It could be interpreted in either way, but my guess is that someone else’s hat would be the default meaning, since losing his own hat could have been unambiguously expressed by using a hata féin.
Go raibh maith agat. I've not been able to find a lot of info on the perfect, so it's still tricky for me.
Gramadach na Gaeilge has a good section on it. Also, it's generally not used in the past or Conditional - Phléigh na daoine é = the people [had] discussed it. - pléadh na daoine é = the people would [have] discussed it