Non-manual markers in ASL are facial expressions, head movements, and body shifts that carry grammatical meaning alongside hand signs. They are not optional add-ons or emotional decoration. In many cases, changing or dropping a non-manual marker changes the meaning of a sentence entirely, making them as essential to ASL grammar as word order is to English.
The Main Types of Non-Manual Markers
Non-manual markers fall into several categories based on which part of the face or body produces them:
- Eyebrows: Raised or furrowed to mark question types, conditionals, and topics.
- Eyes: Widened, squinted, or shifted in gaze direction to indicate size, distance, or referencing a person or object in signing space.
- Nose: Wrinkled to express distaste or used alongside certain signs for emphasis.
- Lips and mouth: Shaped into specific mouth morphemes that act like adverbs or adjectives, modifying how a sign should be understood.
- Head: Nodded, shaken, or tilted to signal affirmation, negation, or questions.
- Body: Shifted left or right to establish different characters or perspectives in a narrative, a technique called role shifting.
Not every sign requires a non-manual marker, but many do. And in several grammatical structures, the non-manual marker is what tells the viewer what kind of sentence they are looking at.
How Eyebrows Signal Question Types
One of the clearest examples of non-manual grammar is the distinction between yes/no questions and WH-questions (who, what, where, when, why, how). In ASL, the difference is not just in which signs you use. It is marked on your face.
For yes/no questions, you raise your eyebrows while signing the question. If you sign “YOU LIKE COFFEE” with raised eyebrows, it becomes “Do you like coffee?” Without that eyebrow raise, the same signs could read as a statement.
For WH-questions, you furrow your eyebrows (bringing them down and together) and often tilt your head slightly forward. So “YOU WANT WHAT” with furrowed brows clearly reads as “What do you want?” This pattern holds across most sign languages, not just ASL.
Negation and Affirmation
To negate a sentence in ASL, you shake your head while signing. This headshake, paired with furrowed eyebrows, can accompany a specific negative sign like NOT or CAN’T, but it can also negate a sentence on its own. Signing “I GO” while shaking your head means “I’m not going” even without a separate sign for “not.”
Affirmation works similarly. A head nod during a statement adds emphasis or confirmation, functioning like “yes” or “indeed” layered onto the sentence. These head movements happen simultaneously with the hand signs rather than before or after them, which is a key difference from how English handles negation with separate words.
Mouth Morphemes and What They Mean
Mouth morphemes are specific mouth shapes held while producing a sign. They function like adverbs or adjectives in English, telling the viewer how something was done or how big, small, fast, or careful it was. They are distinct from mouthing English words. Each morpheme has a recognized form and a consistent range of meanings.
Here are some of the most commonly taught mouth morphemes:
- “OO” (lips rounded into a small circle): Conveys smallness, thinness, slowness, or lightness. Used with signs to mean something is tiny or done gently.
- “CHA” (mouth opens wide): Means very big, very large, very tall, or gigantic. This is the opposite end of the size spectrum from “OO.”
- “MM” (lips pressed together): Indicates something moderate, average, normal, or done with ease. If you sign DRIVE with “MM,” it suggests a smooth, uneventful drive.
- “TH” (tongue protrudes slightly between the teeth): Signals carelessness, foolishness, sloppiness, or distraction. It can also appear in signs related to melting or something being sticky.
- “AAH” (mouth drops open): Conveys far distance or a long duration, depending on context.
- “CS” (teeth clenched, lips pulled back slightly): Means very close or done with effort and struggle.
- Puffed cheeks: Suggests something fluffy, bubbly, or rounded.
- Puckered lips: Indicates something done leisurely or deliberately, as in strolling rather than walking quickly.
A clear example of why mouth morphemes matter: the signs for NOT-YET and LATE use the same handshape and movement, but NOT-YET requires the “TH” mouth morpheme while LATE does not. Without recognizing the mouth morpheme, a viewer cannot tell which word is being signed.
Topicalization and Conditionals
ASL frequently uses a topic-comment structure, where the topic of a sentence is stated first, then commented on. The non-manual marker that signals this is raised eyebrows combined with a slight forward head tilt during the topic portion. For example, signing “PIZZA” with raised eyebrows and a head tilt, then signing “I LIKE” with a neutral face, produces the equivalent of “As for pizza, I like it.”
Conditional sentences (“if/then” constructions) use a similar pattern. The “if” clause is signed with raised eyebrows and a head tilt, and the “then” clause returns to a neutral expression. Without the eyebrow raise on the first part, the conditional meaning is lost and the sentence reads as two separate statements.
Role Shifting and Body Position
When telling a story or reporting a conversation, signers shift their body, head, and eye gaze to represent different people or perspectives. This is called role shifting. You might lean slightly to the right and adopt one facial expression to “become” one character, then shift left with a different expression to represent another.
This is not just acting or dramatic flair. Role shifting is a grammatical device that tells the viewer who is speaking or acting at any given moment. It replaces structures that English handles with phrases like “he said” and “she replied.”
Why Non-Manual Markers Are Hard for Learners
English speakers tend to think of facial expressions as emotional, something you layer on top of words to show how you feel. In ASL, facial expressions are grammatical. Raised eyebrows do not mean you are surprised; they mean you are asking a yes/no question or introducing a topic. A headshake does not mean you are upset; it means the sentence is negative.
This distinction trips up many ASL learners who either forget to use non-manual markers (producing sentences that are grammatically incomplete) or use emotional expressions when grammatical ones are needed. Practicing non-manual markers as part of every sentence, not as an afterthought, is one of the most important shifts in learning to sign fluently.