In English there is not much of a difference between, "Torg lives," and, "Torg is alive," so we decided we should accept both for yIn torgh even though yIn is not a stative verb. I'll double check that no versions with "is alive" are marked as "best translations". Duolingo doesn't really have a way for us to mark a verb as stative or not, since that is not really all that meaningful in English. But in Klingon it makes a big difference, because only the stative verbs can be used adjectively. In The Klingon Dictionary it's a little easier to tell because if the first definition for a word is "be ...", then it's a stative verb. And if the first definition is not "be ..." (even if a later one is), then it's NOT a stative verb.
There are no tenses in Klingon -- there is only aspect.
For example, it's possible to mark an action as completed, but that completion could happen in the past, present, or future ( e.g. "I had written the letter; I will have written the letter"), and it's possible to mark an action as ongoing, but that ongoing action could be in the past, present, or future (e.g. "I was writing a letter; I will be writing a letter").
So bIHegh could be any of "you died; you die; you will die".
But generally not "you have died" (completed) or "you are dying" (on-going) as those would take aspect suffixes.
bI- is the singular "you" and "Su-" is the plural "y'all".
If there is no context forcing it to be singular or plural, either ought to be accepted.
However, there are some sentences in this course that provide context which makes it clear that a singular or a plural interpretation is most appropriate. In those cases where context imposes a singular interpretation a plural "you" will not be accepted. And in those cases where context imposes a plural interpretation a singular "you" will not be accepted.
Since this exercise which you have commented on with your question is fairly early in the course, you have probably not encountered any sentences where the sentence is complicated enough to have such context. But soon you will encounter exercises that use a question and answer format to show whether "you" is singular or plural.
For instance, if the exercise asked you to translate, "Did they hear you? No. They did not hear me." You can see from the answer portion of the exercise that "you" was referring to only one person (the person answering "me").
Or if the exercise asks for a translation of "Can you see me? Yes, we can see you." One can tell that the first "you" matches with "we" in the answer and is plural in the question. And one can tell the second "you" matches with "me" in the question and is singular in the answer.
Carefully consider such sentences, when you get to them, to make sure you are choosing the correct prefix for the indicated "you".
I can hear the difference. The first one is not voiced and the second one is. Does it sound to you like they are both being voiced? Or both being unvoiced?
Correct. They both sound unvoiced to me. I'm no Klingon expert but I am a a linguist and I don't feel that the /ɣ / is being fully realized here. I know this is still being tested so maybe the individual who did the recording didn't know to do so. I find that many of the recordings are quite inconsistent compared to other languages on here.