I wrote "hagamal shelachen?", the female variant as I couldn't hear the difference between an m or an n in the sound file. Should it be accepted? Duolingo pointed out I was almost correct (but not quite) ;)
It's right to tell you that you're almost correct. We can't have it telling you you're completely correct when you're not. There's nothing special about the difference between n and m in Hebrew. It's just like in English. Do you struggle to hear the difference between "then" and "them"?
I want to reiterate what neriah23 is saying. The sound file cuts off towards the end, and it's impossible for me to know what the final consonant sound is. That actually is happening with quite a few audio files with the Hebrew.
It sounds as though the audio was cut off at the end. I had to listen a few times to determine whether it was the male plural or female plural.