The correct distinction between yes/no questions and "wh- questions" in American Sign Language (ASL) primarily involves facial expressions and body language, specifically:
What you do with your eyebrows and how your head is tilted is different when asking yes/no questions than when asking "wh- questions."
For yes/no questions, you typically raise your eyebrows and may lean slightly forward, indicating that you are expecting a yes or no answer. In contrast, for "wh- questions," such as who, what, where, when, and why, you usually furrow your brows and may tilt your head forward slightly, signaling that you are asking for more information.