How can this be understood?
Having thought about it a bit longer, my guess is: "equivocal" means "of the same sound (but of different meanings)", not "of the same voice (= with the same meaning)".
The question then goes into this direction:
Did lat. "vox" semantically evolve into different directions, to mean more of a "sound (vocal)" (transporting possibly equivocal meanings) or more of a "voice" (transporting an unequivocal meaning).
Is there are deeper but comprehensible etymological origin of "vox"?