Some wrongly assume that non-verbal only means physical expression, which is missed if you are on a phone call. This can also mean tone. Consider how two people can use the exact same word choice, yet convey entirely different meanings by their tone of voice. Changing tone can have as much impact as physically rolling your eyes, a dismissive gesture, or an encouraging smile. Listen for tone, ask for clarification, and use your tone to establish understanding. By acknowledging tone you not only increase clarity, but you may also inadvertently be providing feedback by anchoring clear messaging or clearing up misunderstandings.