Does Irish Have an Alveolar Trill?
Is there a rolled or trilled r in Irish?
The older edition of Teach Yourself Irish had this to say about the pronunciation of the Irish of west Munster:
One sound about which a special note is required is r. It is always trilled, never flapped or silent as in English. For broad r there is no further difficulty, but slender r is difficult for English speakers. It approaches the sound of z. (In some dialects it has almost become z.) If you sound a z and then trill it, you will get a fair result.
However, this Wikipedia article based its phonemic chart on Ó Cuív’s The Irish of West Muskerry, Co. Cork, and it shows that an alveolar tap was used in that part of Munster rather than an alveolar trill.