How should I pronounce 'Muiredaig', the name of the clan that later became the O'Tooles. And am I right to pronounce Ui Dunlainge as O'Doolan? Many thanks in advance.
The first word isn't Irish, as far as I can tell. The correct Irish form of the name that was Anglicized as "O'Toole" is Ó Tuathail
Irish surnames are patronymics. They don't have "clans" in the Scottish sense.
The Irish form of the name Anglicized as "Doolan/O'Doolan" is Ó Dúlainn
(pronounced "Oh DOO-len"). The genitive form of that, which would be used for women who married into the family, or in possessive situations, is Uí Dhúlainn
, pronounced "ee GGOO-len."