How do you say hello in southern Ireland?

We speak English here, generally, so "Hello", "Hi", "How are you?" etc. would all be commonly used. There are a few places where Irish is the first language and there the greeting would be Dia dhuit (dee-a gh-witch [the 'gh' as in ghost] would be a close pronunciation). This translates as "God be with you". The 'correct' response is "Dia is Mhuire dhuit", (God and Mary be with you.)