When Louisiana was introduced to the union in 1803, its major language had been French. In 1807, the state adopted English as a condition to admittance to the union. As laws were passed, they typically spelled out which languages may be used to comply with each regulation.

Official English Law in Louisiana

Louisiana Enabling Act, 2 U.S. Stat. 641 § 3 (1811)
And be it further enacted, …that after the admission of the said territory of Orleans as a state into the Union, the laws which such state may pass shall be promulgated and its records of every description shall be preserved, and its judicial and legislative written proceedings conducted in the language in which the laws and the judicial and legislative written proceedings of the United States are now published and conducted…

LANGUAGES SPOKEN IN LOUISIANA

3,771,003	English
382,364	All languages other than English combined
194,314	French (incl. Patois, Cajun)
105,189	Spanish or Spanish Creole
23,326	Vietnamese
8,047	German
5,731	Chinese
5,489	Arabic
4,470	French Creole
3,730	Italian
3,335	Tagalog
2,402	Korean
2,278	African languages
1,810	Japanese
1,564	Gujarathi
1,523	Greek
1,387	Laotian
1,365	Hindi
1,306	Urdu
1,302	Portuguese or Portuguese Creole
936	Russian
914	Persian
806	Serbo-Croatian
710	Scandinavian languages
708	Thai
679	Other Native North American languages
480	Polish
388	Hebrew
382	Mon-Khmer, Cambodian
350	Hungarian
141	Armenian
100	Navajo
75	Yiddish
0	Miao, Hmong