Is it just me, or does the audio for this sound like "khong lai" instead of "khong ai".
Something makes me suspect that you're speaking for yourself there :) I asked my wife on her opinion, as a native Vietnamese speaker. While she had no problems in understanding the audio herself, she could relate to why I might think that there was an "l" in there, due to the speaker of the phrase not leaving a gap between the words "khong" and "ai" as he speaks them. So that hasty transition between words does give this impression of something like "khonglai".
Anyway, not being critical of the native speaker here, just sharing how the experience of listening is like for the non-native listener. I'll just let my ears accommodate for this sort of subtle variation.
I recall others in these forums also mentioned they had problems with the pronounciation of the speakers use of the word "mot" too (saying it sometimes sounded like "mon"), so I don't feel that I am alone in such mishearings.
Well, I had a re-listen just now and I agree that I can no longer hear the "l" I heard when I reported this 2 months ago. So there is the possibility that my feedback was received and acted upon, with a re-recording made.
Another possibility I accept is that after working on the course for so long and listening to the speaker all that time, my ears finally "tuned in" to his pronounciation and I'm no longer hearing it the way I used to hear it.
Either way, I'll clarify though that Tehvanarch's view at the time was that it was "just me", and that was already refuted, as my vietnamese wife bore witness to what I heard 2 months ago and could empathise with my perspective.
I listened thoroughly several times over and did not detect any Ls at the time. Now, I'm not going to accuse anyone of anything but let's just leave it at that.