Illustrator does not show diacritical marks (right ALT+letter)

[paulinag79]

On my new computer (Windows) Illustrator does not enter diacritical marks (special character of Polish language) after I use right ALT+letter. The font is appropriate. I think that on the old computer my friend fixed it somehow changing default shortcuts... Anyone any idea how to fix the problem on a new computer???

[Met1]

You should ask your friend what they did.

I assume the diacritical is visible in the glyph pallette?