Although highly unlikely, it's possible, we suppose, that all these distinguished publications repeatedly misheard the same individual in the same way, although he has no speech impediment that we know of.
The publications doubted that they misheard him repeatedly. 
mnli hypothesis: The publications doubted that they misheard him repeatedly.  premise: Although highly unlikely, it's possible, we suppose, that all these distinguished publications repeatedly misheard the same individual in the same way, although he has no speech impediment that we know of.