Understand in Sign Language: How to Sign It and Check It on Camera

The short answer

In American Sign Language (ASL), the sign for “understand” is made near the side of your forehead. Hold your dominant hand in a loose fist with the index finger tucked against the thumb, palm facing you. Then flick the index finger up so it points upward. The motion suggests an idea suddenly clicking into place in your head.

The same sign is generally used for “understanding.” ASL does not add an “-ing” ending the way English does. Whether you mean the verb or the noun comes from context, word order and facial expression, not from a separate sign.

Which sign language do you need?

Sign languages are not universal. ASL is the main sign language in the United States and much of Canada. British Sign Language, Russian Sign Language and others are separate languages with their own vocabulary. A sign for “understand” in one of them may not be recognized in another.

This guide describes ASL only. If you are communicating with someone who uses a different sign language, such as Russian Sign Language, learn that sign from a fluent signer of that language or a reputable dictionary for it. The supplied material contains no verified description of the sign in other sign languages. Even within ASL, regional and personal variations exist, so the person you are signing with may use a slightly different form.

Step by step: signing “understand” in ASL

• 1. Use your dominant hand: your right hand if you are right-handed, your left if you are left-handed.
• 2. Form a loose fist and tuck the tip of your index finger against the pad of your thumb.
• 3. Bring the hand up beside your forehead, near the temple, with your palm facing toward you.
• 4. Flick the index finger upward in one quick motion, so it ends straight and pointing up.
• 5. Keep the movement small and crisp. A single flick is usually enough.

Related phrases

• “I understand”: point to yourself, then sign UNDERSTAND. A small nod reinforces the meaning.
• “Do you understand?”: sign UNDERSTAND, often followed by pointing toward the other person, with raised eyebrows and a slight forward head tilt. In ASL, that facial expression marks a yes-or-no question.
• “I don’t understand”: sign UNDERSTAND while shaking your head, usually with a slight frown. The head shake carries the negation.

Facial expressions in ASL are part of the grammar, not optional extras. Signing UNDERSTAND with a neutral face, a questioning face or a head shake can turn the same handshape into a statement, a question or a negative.

Checking your sign on a webcam

If you will use this sign on a video call, check that the other person can actually see it. The sign happens beside your head and depends on your face, so framing matters more than it does for spoken conversation.

• Framing: open your camera preview and make sure the frame shows your head, shoulders and the space around your head where your hands move. If your hand leaves the frame during the flick, move back or widen the view.
• Lighting: light your face and hands from the front. A bright window behind you can turn your hand into a dark shape.
• Background: a plain physical background that contrasts with your skin tone and clothing makes hand shapes easier to read.
• Virtual effects: background blur or a virtual background can sometimes blur or cut off fast-moving hands. If your index finger flickers or disappears in the preview, try turning the effect off.
• Movement: video calls may compress fast motion. If your flick looks smeared in the preview, slow it slightly while keeping it distinct.

Seeing yourself in the preview only confirms that the camera is capturing you. It does not guarantee how the video looks on the other end, because connection quality can reduce clarity. To verify the result, ask the person you are calling whether they can see your hands and face clearly, or test with someone in advance.

Limitations of this guide

A written description cannot fully show handshape, speed and facial expression. To make sure your sign looks natural, compare it with a video from a fluent ASL signer or ask a Deaf or fluent signer for feedback. If you need a sign language other than ASL, treat this description as not applicable and look for a source specific to that language.