Illinois designated English as the official state language in 1969 (one of the first states to make English the official language). The foreign languages most commonly spoken as the primary language in a home in Illinois are Spanish, Polish, German, Tag
The law designating English as the official Illinois state language is found in the Illinois Compiled Statutes, Government, Chapter 5, State Designations Act, Section 20.
GOVERNMENT
GENERAL PROVISIONS
(5 ILCS 460/) State Designations Act.
5 ILCS 460/20) (from Ch. 1, par. 2901-20)
Sec. 20. Official language. The official language of the State of Illinois is English.
(Source: P.A. 87-273.)