Folk Awareness oif Dialect

[Douglas G. Wilson]

>I've never heard anyone from Illinois pronounce it with the the z on the
>end. ... I have heard non-Illinoisians say it with the z though.

Same here. The RHUD says it as well as I can:

"The pronunciation of ILLINOIS with a final (z) , which occurs chiefly
among less educated speakers, is least common in Illinois itself,
increasing in frequency as distance from the state increases."

-- Doug Wilson