Funny language Barrier moments are part of the fun and are not generally meanspirited. But what Kiara does is different. Sorry if you don't see it, but with her, the "joke" ALWAYS goes like this:
Kiara "You say it '(insert word)".
Other Vtuber: "(word not correctly pronounced)"
Kiara: HaHahaaahahaha, nOOOO not like that!!!
It's a big deal because there is a person right there with you laughing (and it really seems to be at you). And I'm sure you all know English in most of the civilized world is considered a super valuable and important skill to have. Especially in Japan.
And having someone point out how not good you are in that skill, even in a slightly condecending way (or laughing), can make the other feel like getting called a dum-dum or uneducated and lazy for not having learnt it. (Oh, you suck at English. hahahah, I can speak english, german AND japanese hahaha you dum-dum)
That's why having laughing at English mistakes right next to you is not the same as your buddy laughing at you for crashing in Mario Kart.
As Christopher Hitchens said "Austria's biggest achievement was convincing the world Hitler was German and Beethoven was Viennese"
Seriosly now, Hololive is supposed to be fun. The chicken makes all her "learning" collabs unbearable by her petulancy and lack of tact. If it's common for Austrians to do that, then they suck.