Dialects of Irish
Pronunciation, grammar, and word choice in Irish entirely depends on the dialect, broadly:
Gaeilg Uladh, spoken in parts of Donegal, has the highest number of remaining sounds from Old Irish. It also has similarities to Scottish Gaelic.
Gaeilge an Iarthair, spoken in parts of Galway, Mayo, and Meath, has many contracted sounds that give a distinct feel to the language.
Gaelainn na Mumhan, spoken in parts of Waterford, Cork, and Kerry, has many survivals from Old Irish grammar as well as historical influence from French.
Leinster Irish doesn't have a surviving native dialect, but we can learn about it what it may have been like from place names.
Standard Irish (the Caighdeán, or Gaeilge na Leabhar ‘Irish of the Books’) is a written standard and is not designed to have any direction on pronunciation. Each dialect has its own pronunciation, grammar, and vocabulary, and they all contribute to the rich history of the Irish language. Understanding the dialects helps us pronounce words correctly and speak Irish well.