Illinois was one of the first states to make English its official language, doing so in 1969 (see below).

Official English law in Illinois (1969)

Illinois Statute:
Chapter 5, Section 460/20 – Official Language (1969)
The official language of the State of Illinois is English.

LANGUAGES SPOKEN IN ILLINOIS

9,326,786	English
2,220,719	All languages other than English combined
1,253,676	Spanish or Spanish Creole
185,749	Polish
65,251	Chinese
63,366	German
62,367	Tagalog
51,975	Italian
43,712	Korean
40,812	French (incl. Patois, Cajun)
40,581	Greek
38,053	Russian
35,397	Arabic
32,420	Urdu
29,631	Serbo-Croatian
28,725	Gujarathi
18,734	Hindi
16,487	Vietnamese
15,481	Japanese
15,379	African languages
6,466	Scandinavian languages
6,288	Thai
6,076	Persian
5,705	Hebrew
4,835	Laotian
4,270	Hungarian
4,194	Portuguese or Portuguese Creole
4,035	French Creole
3,509	Yiddish
3,236	Mon-Khmer, Cambodian
2,326	Armenian
1,245	Other Native North American languages
413	Miao, Hmong
125	Navajo