I've just got the "repeat what you hear", with one of the female voices. I'm convinced I heard "buHoH" - which even was accepted as answer, even though I then realized there is no bu- . I think the sample is called "__lottie_element_2119"?
So, I'm probably mishearing it (new headphones), but the answer definitely shouldn't have been accepted. Why does this happen anyway? I understand having problems with upper/lower case, and even the apostrophe - but bu- instead of lu- is completely different?
I hear what you're hearing. The sentence should be recorded again, because it DOES sound like buHoH, and buHoH is not a word in Klingon.
Qov is speaking, first sentence on this page: https://www.duolingo.com/dictionary/Klingon/luhoh/d0809c5e87662366626b2b152106a4a8
The system automatically accepts one letter substitutions as a typo and the listening exercises never tell you when you have a typo. It seems like a bad way for the system to work if you ask me, but the staff have known about it for a long time and still haven't changed it, so I guess it doesn't seem urgent to them. I recommend you submit it as a bug report: https://support.duolingo.com/hc/en-us/articles/204728264-How-do-I-report-a-bug-