How Does Sign Language Work?

Sign language is a full language, not mime

The five parameters build every sign

note

The five parameters of a sign

1. Handshape
2. Movement
3. Location
4. Orientation
5. Non-manual expression

Why they matter

A small change in one parameter can change meaning.

Examples of what can change

• Handshape: which fingers are extended
• Movement: straight, repeated, circular, or single motion
• Location: face, chest, neutral space, or another body area
• Orientation: palm up, down, in, or out
• Expression: eyebrows, mouth, gaze, and head movement

Linguistic takeaway

Sign languages are built from contrastive units, just like spoken languages are built from distinct sounds and word patterns.

illustration

diagram

equation

$$\text{A sign} = f(\text{handshape},\ \text{movement},\ \text{location},\ \text{orientation},\ \text{expression})$$

ASL, BSL, and why sign languages are not universal

Grammar in space: how sign languages build meaning

Deaf culture, language rights, and cochlear implant debates

Transcript

Welcome to Slate. Today we're looking at How Does Sign Language Work?. We'll cover Why sign languages are full natural languages with complex grammar, ASL vs. BSL vs. other sign languages — they are not mutually intelligible, The five parameters: handshape, movement, location, orientation, expression, and Deaf culture, cochlear implant debates, and language rights. Let's get into it.

Sign language is not a backup version of speech. It is a complete human language. The same brain systems used for language are active in signers, and sign languages have grammar, vocabulary, and ways to say things that are not copied from English or any spoken language. Here is the key idea: a sign language is built to carry meaning efficiently through the eyes and hands. Think of it like a different operating system, not a different app. It does the same job, but with its own rules. Linguists have studied this for decades. William Stokoe showed in 1960 that American Sign Language, or A-S-L, had the structure of a real language. That work changed the field. Before that, many people wrongly assumed signing was just gestures or pantomime. But mime tries to act out meaning directly. Sign languages use conventional signs. They have word order, morphology, and ways to mark questions, negation, time, and aspect. A simple example: in A-S-L, facial expression can change the meaning of a sentence. Raised eyebrows can mark a yes-no question. A head shake can mark negation. The face is not decoration. It is part of grammar. That is one reason sign language is so rich: the hands carry one layer of meaning, and the face and body carry another.

Most signs are built from five main parameters. If you change one, you can change the meaning. That is a lot like changing one ingredient in a recipe. The result can be a completely different dish. The first parameter is handshape. This is the shape the hand makes. A flat hand, a fist, or a pointing hand can all mean different things. The second is movement. A sign may move up, down, in a circle, or repeat. The third is location. A sign made near the forehead can mean something different from the same handshape at the chest. The fourth is orientation. Which way the palm faces matters. The fifth is non-manual expression. That includes eyebrow position, eye gaze, mouth shape, head tilt, and body posture. These parameters work together. In many sign languages, minimal pairs show that one small change creates a new sign, just as changing one sound in spoken language can change a word. The exact details differ from one sign language to another, but the principle is the same: signs are structured, not random. Notice how much information the face carries. In spoken language, tone of voice can signal attitude or questions. In sign languages, the face often does that job directly and grammatically.

American Sign Language and British Sign Language are not mutually intelligible. That surprises many people, because English is used in both the United States and Britain. But sign languages do not follow spoken-language borders. They grow in communities, schools, and social networks. ASL and BSL have different histories, different vocabularies, and different grammars. ASL is historically related to French Sign Language because of the school founded by Thomas Hopkins Gallaudet and Laurent Clerc in 1817. BSL developed along a separate path in Britain. So two sign languages can be as different as French and German, even when the spoken languages around them are both English. There are many sign languages worldwide. Linguists estimate hundreds exist, and they are not all related. In some places, there are national sign languages, regional varieties, and village sign languages used by both deaf and hearing people. So “sign language” is not one language. It is a family name for many languages. This matters in real life. A Deaf person from the United States may not understand a Deaf person from the United Kingdom without adaptation, just as speakers of different spoken languages may need translation. Shared culture does not automatically mean shared language.

Sign languages use space in ways spoken languages usually do not. A signer can place people or objects in different spots in front of the body, then refer back to them by pointing or directing a sign toward that location. That makes space work a bit like a map. Once a person or idea is placed on the map, the signer can refer to it again without repeating the whole description. This is one reason sign languages can be very efficient. They can show who did what to whom by the direction of a sign. They can also use classifiers, which are handshapes that represent categories such as a person, a vehicle, or a flat object. These are not random hand motions. They are grammatical tools. Questions and conditionals often rely on facial grammar. A yes-no question may use raised eyebrows. A wh-question, like who or what, may use lowered brows and a different head posture. In many sign languages, facial markers span a whole phrase, not just one sign. That is different from spoken language, where grammar is mostly carried by word order and sound. Think of it like subtitles for grammar built into the face and body. The hands carry the main content. The face tells you how to read it.

Language is never only about grammar. It is also about community and rights. Deaf culture is built around shared experience, visual communication, and pride in sign language. Many Deaf people see themselves not as broken hearing people, but as members of a linguistic minority with a distinct culture. That matters in education. Research over many years has shown that early access to a fully accessible language supports cognitive and social development. For many deaf children, that means sign language from the start, whether or not they also use hearing technology. Cochlear implants can help some children detect sound and support spoken language learning, especially when combined with early intervention. But they do not guarantee fluent spoken language, and they do not replace the need for language access. The debate is not really “sign language or technology.” It is whether children get a language they can fully access early enough. A child who has no accessible language in the early years can face long-term harm. That is why language rights matter. Families, schools, and governments need to make sure deaf children can learn a natural language from the beginning. The visual lesson here is simple: access first. Method second. A child needs language the way a plant needs water. The form can vary, but the need is nonnegotiable.