How to develop interpersonal skills<br>Learn what makes up nonverbal communication. Nonverbal communication includes your facial expressions, your use of touch, and your voice (not the words you speak, but how they sound). Visual cues are more important to interpret and deliver than audio cues.
In discussing non-verbal communication, your voice refers to both the words you speak and how they sound.    
According to the agent, when discussing non-verbal communication, your voice only refers how your words sound and not the words you speak (see brackets).  However, this would confuse the system because usually a person's words are also a form of verbal communication.  
( z1 refer :ARG0 ( z2 voice :part-of ( z3 you ) ) :ARG1 ( z4 and :op ( z5 word :ARG1-of ( z6 speak :ARG0 z3 ) ) :op ( z7 have-manner :ARG1 ( z8 sound :ARG1 z5 ) ) ) )