We've received a couple complaints from Catalan donors saying they got their TY in English when they donated through the Catalan Wikipedia. I thought it was simply donor error, but after we heard from about 5 donors, I tested the flow.
I donated through the donate.wikimedia.org/wiki/Special:FundraiserLandingPage?uselang=ca&country=ES page and the flow was mostly in Catalan, but I got to an English TY page and an English TY letter. Civi has my preferred language as "unknown" for this donation (see: https://civicrm.wikimedia.org/civicrm/contact/view?reset=1&cid=10907250).
It would be great if we could fix this ASAP so our list for emails next year is as correct as possible, and so we thank caES donors in the correct language.