Why facial expressions matter in sign language

The short answer

Yes. Facial expressions are essential in sign language. In American Sign Language (ASL) and other sign languages, the face does more than show feelings. It carries grammatical information. The same hand signs can form a statement, a question or a negation depending on what the eyebrows, eyes, mouth and head are doing. If you remove the facial component, a signed message can become unclear or change its meaning. One limit applies: sign languages are distinct languages, so the specific expressions described here come from ASL, the language most relevant to US readers. Other sign languages use the face in comparable ways, but their details differ.

Grammar on the face: non-manual markers

Linguists use the term non-manual markers for meaningful signals that do not come from the hands. These include eyebrow position, eye gaze, mouth shapes, head movement and shifts of the shoulders or torso. In spoken English, a rising tone can turn a statement into a question. In ASL, much of that work is done visually, mainly by the face.

• Yes/no questions: eyebrows are typically raised, often with the head tilted slightly forward.
• Wh-questions (who, what, where, when, why, how): eyebrows are typically drawn together or furrowed.
• Negation: a side-to-side headshake can negate a sentence, sometimes with no separate sign for "not."
• Topics and conditionals: raised eyebrows can mark the topic of a sentence or an "if" clause before the main statement.
• Affirmation: a nod can confirm or emphasize that something is true.

Because these signals are part of the grammar, a learner who signs correctly with their hands but keeps a neutral face may still be misunderstood. For example, a sentence meant as a question can come across as a plain statement.

Mouth morphemes and adverbial meaning

ASL also uses specific mouth shapes, often called mouth morphemes, to change or add meaning to a sign. These work much like adverbs or adjectives. ASL teaching materials commonly cite examples such as a pressed-lips shape for doing something normally or with ease, a shape associated with "large" or "a lot," and a tongue-showing shape for doing something carelessly. The exact forms and meanings are taught as part of the language and vary by region and community. Mouth morphemes should not be confused with mouthing English words, which some signers do and others do not.

Emotion and tone still matter

Facial expressions also do their familiar job of conveying emotion, attitude and emphasis, much as tone of voice does in speech. A signer may show surprise, sarcasm or urgency through the face. Grammatical and emotional expressions often happen together, and fluent signers learn to combine them. Listeners, often called viewers in signing contexts, read both layers at once.

Body language in signed communication

Beyond the face, the head, shoulders and torso also carry meaning. A common technique is role shift. The signer turns their shoulders or changes eye gaze to show that they are quoting or acting as a different person in a story. Eye gaze and pointing can also set up locations in the signing space that stand for people or things, which the signer can refer back to later.

For people interacting with Deaf or hard-of-hearing people more generally, some widely described courtesies apply. Keep eye contact while communicating. Get attention visually, such as with a wave within sight or a light tap on the shoulder. Avoid covering your mouth or face. Keep in mind that not all deaf people use sign language. Some rely on lipreading, captions, writing or a mix of methods, so asking about preferences is better than assuming.

What this means for signing on camera

Since meaning lives on the face as well as in the hands, video calls with signers depend on the camera showing both clearly. The following are general principles rather than tested settings:

• Frame the head, face and upper body, with room for the hands to move without leaving the frame.
• Light the face from the front. Strong light from behind, such as a window, can darken the face and hide eyebrow and mouth movement.
• Avoid anything that covers the face, such as a hand resting on the chin or a non-transparent mask.
• A plain, uncluttered background can make hand and face movements easier to see.
• If your conferencing app lets you pin or spotlight a participant, using it for the signer or interpreter helps keep their video large and visible.

Where webcam audio fits, and gaps in this guide

Signed content is visual, so a webcam's built-in microphone does not capture it. Audio becomes relevant in mixed meetings. Examples include a sign language interpreter voicing for hearing participants, or hearing participants speaking so their words can be interpreted or captioned. In those cases, the speaker's microphone quality affects how accurately interpreters and captioning tools can follow along. No evidence was supplied for this article about specific webcams, microphone specifications, captioning accuracy or conferencing app settings. For that reason, this guide does not make product or setting recommendations for those areas.