I create a freestyle job, which runs a trivial shell script:

echo language $language
echo LANGUAGE $LANGUAGE

I create it as a freestyle job with two string parameters (`LANGUAGE` and `language`).
When I set the parameters (using the GUI configurator) to:

LANGUAGE=zu-UO
language=sa-TN

The output is:

language
LANGUAGE sa-TN

While it should be

language sa-TN
LANGUAGE zu-UO

And what's more: when i configure the same parameter values, but the order of parameters in the job configuration is reverse (yes, I just dragged one and moved it in the GUI), and so I set:

language=sa-TN
LANGUAGE=zu-UO

The output is DIFFERENT! this time:

language sa-TN
LANGUAGE

Which, anyway, is still wrong, though, as it still should be:

language sa-TN
LANGUAGE zu-UO

This happens on a clean setup with default plugins prepared in a docker container from your dockerhub, both on current lts (2.204.1) and on latest (2.209).

At this point, I simply do not now how to configure my jobs' parameters.
Within my real setup (currently on 2.176.3) jobs that used to successfully work when configured with a parameter named `language` (even if there is no uppercase parameter named `LANGUAGE`** so there cannot be a upper-lower-case collision) now randomly start to misbehave - the parameter `language` isn't even set. Changing anything (even totally unrelated) in a job configuration results in blowing up a working configuration where the 'language' variable has been used for a long time without any problems.