I have Ubuntu 21.10 (recently upgraded from 20.04) on an 8G RPi-4 connected to a touchscreen and a mini keyboard. Using the Budgie desktop and a USB power block as a battery it makes a very nice portable desktop computer, and I mainly use it for writing and for coding C and HTML. For coding I mostly use Geany.
Since the upgrade it has become almost unusuable for C coding, because the keys that used to generate double-quotes (ASCII code 34) and single-quotes (ASCII code 39) no longer do that. Instead they generate extended character quotes that the compiler chokes on.
I have messed about with different keyboards (I live in Ireland and use UK keyboard layout) and changed locales, even editing /var/lib/locales/supported.d/en and rebuilding it, but nothing I can do will restore the old, straightforward ASCII behaviour. Sometimes deleting and replacing keyboard layouts allows ASCII behaviour for a while, but it never survives upgrade.
This has been ruining my mornings for days, and my Google-fu is no good here: all I can find is description of how to use the fancy new internationalisation features to enter accent marks, not how to turn the thing off and go back to plain-old ASCII.
The five accent marks that Irish does use can be obtained from alt-gr just like the old days, but that would be a bonus. I write more C than Irish, and I just want an ASCII keyboard, like I have been using since the 1970s.
Help?