The Circular Reasoning Underlying 'Semovergence Implies Sonovergence'

Ngo, Hood, Martin, Painter, Smith & Zappavigna (2022: 200):

It is probably fair to say that when semovergent paralanguage is deployed, it will almost always be coordinated with TONALITY, TONICITY and RHYTHM; this argues that semovergence implies sonovergence. Sonovergent paralanguage on the other hand can be deployed without semovergence, through gestures and body movement in tune with or in sync with prosodic phonology (but no more).

Blogger Comments:

[1] This is an example of the logical fallacy of circular reasoning known as begging the question' (petitio principii), because the argument's premiss assumes the conclusion instead of supporting it. 

Premiss: semovergent paralanguage is co-ordinated with textual phonology

Conclusion: semovergent paralanguage is co-ordinated with textual phonology (= sonovergent)

[2] To be clear, this is because language ("sonovergent paralanguage") can be deployed without body language ("semovergent paralanguage").