What, exactly doe it mean that you cannot use any language besides English? Has the interface language changed, or you cannot assign languages to text?
I can type only i english, even that I have 2 other languages on the system (in all other apps on the computer i don't have this problem - only with In design)
Are you saying that InDesign does not recognize alternate language keyboard layouts? That's outside my area of experience, but we may have others here who can help.
You said CS6, is this a perpetual license, or a Creative Cloud subscription version, and which build (minor version number : 8.?.?)? What OS?
What do you mean, you can type only in English? I am pretty sure that you can input via keyboard any letter you want to form words in any language you wnat to write and to change to a font which supports other languages.
Did you select the correct languages in the Paragraph and Character Properties, which should be saved in a correct Paragraph and/or Character Style?