Why is "teastaionn caife o tu" wrong?
ó tú becomes uait. Otherwise, in the standard, that'd be correct (note that teastaigh can only mean 'need' in Connacht Irish)
I'd have always said something like "tá caife ag teastail uait" is there a reason why Duolingo doesn't accept this construction?
I would also say ag teastail uait
what is the difference?
Is "ba mhaith le" a Connemara construction that no one else uses? "Tá caife uait" sounds to me like "You are missing a coffee," like maybe you're a waiter and you don't have the full order on your tray to bring to the table.
ba mhaith le uses the conditional form of the copula, and means "would like".
Is maith liom caife - "I like coffee"
Ba mhaith liom caife - "I would like coffee"
tá caife uaim - "I want/need coffee"