CARDIFF, Wales — There was a time when Irish and Scottish immigrants in the United States were jealous of their Welsh cousins, who had not just their patron saint and their resentment of the English to bind them together — but also their very own language.

A lively Welsh-language press once thrived in the United States. In the 1860s, a daily newspaper, three monthly journals and a range of books were published in Welsh there, said Jerry Hunter, a professor at Bangor University.

As one Welsh-American told an Irish-American at the time: “On St. Patrick’s Day, you go to the pub and speak the language of the enemy. On St. David’s Day, we go to the chapel and speak Welsh.”

But as the Welsh language withered from one generation to the next, much of Welsh-American identity withered with it. If today it is mainly the Irish and Scottish diasporas that endure in the United States, it is not just because they were always more numerous.