Verbal communication is just one aspect of human communication. Paraverbal, nonverbal and extraverbal communication channels are central to interpersonal interaction. What cannot be communicated through words alone can be readily understood when supported by paraverbal (or paralinguistic) cues, such as pitch, volume and intonation; by nonverbal (or nonlinguistic) cues, such as facial expressions, eye contact, and gestures; and by extraverbal (or extralinguistic) cues, such as time, place and context.
This is why it is so difficult to learn English in a classroom where the focus is on words and rules and communication is devoid of life and context.