"I never thought about myself," claims senior citizen Joe (Jim Norton) in playwright Conor McPherson's Port Authority. Yet he does. A lot. So do middle-aged Dermot (Brian d'Arcy James) and twentysomething Kevin (John Gallagher, Jr.). The three generations of Dubliners tell their stories of love and loss in a series of lyrical monologues (in which the Irish slang is mercifully intact). Norton, who originated the role of Joe, may have the slight advantage — but d'Arcy James and Gallagher's singing backgrounds are assets in delivering McPherson's lilting language.