A it has been proved that unclear language has triggered most aircraft accidents and near collisions.
B it has been undeniable that inadequate communication is the major source of accidents and near accidents in aviation.
C it has been difficult to attest that language mistakes have been responsible for a large number of airplane accidents and near crashes.
D there has been a slight suspicion that most airplane accidents and near accidents have been caused by the ineffective communication.
E there have been strong indications that linguistic misunderstandings have played a significant role in aviation accidents and narrowly avoided collisions.