So this only affects the language "re" under ConfirmEdit/i18n/re ? Or is this also a problem in English language?

This is about reCAPTCHA, not a 're' language..

I don't think this is actually needed as Google's new No CAPTCHA is being implemented as a new one instead of updating the existing one. See T84918: Use the modernized reCaptcha API, which hopefully allows for intervention-free verification and associated patch,

After reading about the noCaptcha and reCaptcha, I think if we use the former, this is not needed. If we use the latter, i think a user still may have multiple words. Anyhow, if this needs to be done, i can do it. https://github.com/wikimedia/mediawiki-extensions-ConfirmEdit/blob/master/ReCaptcha/i18n/en.json That is the file, and I would just have to change all the plural nouns to singular?

As the reCaptcha module is marked as deprecated (T142133) and will be removed in a later version of this extension, I wouldn't invest any time in this module anymore. So, I'll mark this task as declined. However, thanks for your offer @MtDu! :)