An important note here… Linguistically, sign language is not “non-verbal.” There are words, morphology, grammar, syntax, semantics, structure, conventions, and all. In this context “verbal” means linguistic which is a different term than “spoken.”
I’m an ASL linguist, so those particulars are important to me.
Spoken information can be linguistic, and can also be paralinguistic (pauses, drawing words out, tone, pitch, breathing patterns, onomatopoeia, beatboxing)
Non-verbal/paralinguistic expressions express thoughts in conventionalized ways (like a shrug) without the use of of a specific language structure. That means writing is still also verbal.
Some ways to communicate non-verbally: proximity (standing too close or backing off fast), body positioning (manspreading, hugging torso), breathing (sighs, sharp intakes)
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