Dia dhuit (Dia duit in Ulster) doesn't have a 'w' sound altho it may sound like it in quick speech. It's more like a 'short-u' glide rather than 'w'. In Munster it would sound like 'deea gh(u)it' but in Connacht more like 'd'yeea gh(u)itch'.
It's regarded as quite formal nowadays. (2k3r021)
Previous answer:
In different parts of Ireland the pronunciation may vary. Generally it is pronounced, "Deea gwit". The a is a soft a, so pronounced like the a in tramp, rather than in tray.
Thug sé úll duit. It would be pronounced: "Hug shay ool dit"
Most people in Ireland speak English so they would say Merry Christmas or commonly Happy Christmas. If they are using the Irish language, they will say "Nollaig shona duit" which is pronounced "Nullig huna dit".
In Irish: Lá Naomh Vailintín shona duit. or Beannachtaí na Féile Vailintín duit.
God be with you: Dia duit May God be with you too: Dia is muire duit That is also what people say to say hello in Irish if you say "Dia duit" the other person should say "Dia is muire duit"
The Irish language.
To you all in Irish A thabhairt duit go léir
Dia duit
deoch a cheannach duit
Dia duit
"mora duit ar maidin" means "good morning" in Irish.
In Irish it's "tabhair póg duit".
Dia duit, conas atá tú?