4 Building number. 9 Street is also used frequently. Back to top Language and Alphabet Gaelic and English are both official languages of Ireland, but English is used for all business purposes. Spelling conventions in English are British. Given names are called Christian names .
People usually use one given name followed by their family name.
It is a little more formal to use a middle initial. Irish businesspeople normally use their given names with each other, except on a first contact with someone outside their organization, when the use of Mr. or Ms. is expected. Many family names begin with O' or Mac or Mc . You should address her as Dear Ms. Smythe O'Callaghan . Many Irish people have given names that can be spelled in either Gaelic or English.