In this era, education was entirely a state responsibility. But it is true that Louisiana did move away from bilingualism after the Civil War.Well, I was thinking in Act of 1774 in Canada. About USA.. I think after 1865, they wanted a a country culturally unified and they just did it through teaching in school.
I'm not saying it was good or bad, I'm not judging, but I think the system worked ... By imposing English, most North Americans (who did not come from English-speaking countries) ended up feeling part of a new community.
Public education in the United States was generally in English. But there was a particular crackdown on the use of other languages (particularly German) when the "Americanism" movement peaked during World War I: During World War I, U.S. Government Propaganda Erased German Culture
The obsession with restoring white rule after Reconstruction meant that white Francophones had an overwhelming incentive to emphasize the "white" parts of the identity. It also meant that there was no possibility of forming interracial coalitions of French-speaking whites and blacks.