Ireland's language shift: when Irish speakers switched to English

How Many People Speak Irish, And Where Is It Spoken?

Ireland recorded the Isle Of Man’s last native speakers of her Gaelic language Manx. The Manx language was dying out, with only a handful of elderly native speakers still alive in the late 1940s. A visit by DeValera, the Irish leader, resulted in recording equipment being bought and an Irish folklore collector sent to the Isle of Man with it in a recording van. He travelled to remote areas and recorded elderly people, probably born in the nineteenth century, whose mother tongue was Manx. Similar

A brief history of the Irish language | Britannica