Summertime,
For what it's worth, I also know my speech and communications isn't clear when in POIS 3/4 day phase. My missus regularly says I am mumbling, but I have always put that down to the depression side of the condition, and what has been better articulated on this board as cognition, brain fog etc, but maybe there is more to it than that, as you seem to have a more frustrating outcome from POIS onset.