I meant to yesterday, but I ended up getting side tracked! But I just completed it now. I still can't believe they didn't fix the "Back" and "Next" buttons though.
I believe all of the researchers are German. But what's odd is that Germans normally are fairly proficient in the English language because they are pretty much taught it in schools from 5 years old and onwards.
I figured, I'm sure most people will either figure out or translate those buttons. I noticed a question or two that read like it went through translate lol. But it was still ok.