Acrobat Reader running on Monterey – text box problem

I recently upgraded to Monterey, 12.1, and when using the comments in Acrobat Reader DC (version 21.011.20039), the app suddenly and without obvious cause started throwing up the following alert when I try to add text to a text box when commenting:

An error has occurred that may be fixed by installing the latest version of the Traditional Chinese Language Support package.

I'm in the UK and have no need for Chinese language support. And the app was working fine until it...wasn't. The problem is compounded by the fact that so far I've been unable to track down this 'Chinese Language Support package', too.

Does anyone have any advice or info that may help? I'm pulling my hair out here! The problem seems to be confined to text boxes, and all other commenting tools are working fine. I just can't understand it.

Thanks.