Today, let’s switch gears a little. Until now, we’ve been learning about languages that have sound systems. If you’ve been following previous editions of this series, you’ve probably noticed that sound-based languages, despite lexical, grammatical and pronunciation differences, still have a lot in common. Every language has a patterned logic, which makes it learnable.
But not all languages have sound systems. Deaf people can’t hear sound, so they cannot learn to imitate the sound of speech as well as hearing people can. Instead, they’ve created their own ways to communicate needs, affection and ideas, along with complex scientific and artistic concepts through forming icons with their hands, supported by body movement and precise culturally-bound facial expressions worthy of admiration in the dramatic arts.
We’ll begin with the American Sign Language to be able to make a comparison between English and other languages, and then move to some other examples of sign languages, to give you at least a surface idea of how they differ.
A Brief History of Sign Languages
Natural sign languages emerged wherever groups of Deaf people interacted with each other and also had to communicate with hearing people. Some modern sign languages were born in educational institutions. One of the most influential moments occurred in 18th-century France, when Abbé Charles-Michel de l’Épée established the first public school for Deaf students in Paris.
Nearly a millennium later, in 1817, Thomas Hopkins Gallaudet and Laurent Clerc founded the American School for the Deaf, when Clerc brought Old French Sign Language with him to America. It mixed with existing local sign systems used by Deaf communities in the United States and Canada.
Simultaneously, other teachers from the Paris school for the Deaf travelled to spread Old French Sign Language (LSF) to other parts of the world where it influenced the creation of the Irish, Italian, Russian, Dutch, Arabic, Brazilian and many other sign languages.
Today, linguists estimate there are over 300 distinct sign languages worldwide.
A Little Island Shaped American Sign Language (ASL)
One of the most unusual linguistic stories in the world comes from Martha’s Vineyard, a charming island off the coast of the State of Massachusetts in the United States.
From the 17th through the 19th centuries, the island had an unusually high rate of hereditary deafness. Geographic isolation contributed to a genetic mutation resulting from a small reproductive gene pool. In some villages, 1 in 25 residents was deaf, and in certain areas the ratio was even higher.
In this highly inclusive tight-knit community, sign language was a part of everyday life. Hearing children grew up learning both spoken English and signing, much like bilingual communities speak different languages today. On this island, both Deaf and hearing people worked and lived alongside of each other and because everyone signed, deafness did not carry the same stigma and social limitations found elsewhere. Here, residents used a local sign language called Martha’s Vineyard Sign Language.
This made Martha’s Vineyard one of the earliest documented examples of full linguistic accessibility.
When the American School for the Deaf opened in 1817 in Hartford, in the nearby State of Connecticut, many of its first students came from Martha’s Vineyard. At the school, three signing systems came together: Martha’s Vineyard Sign Language, Old French Sign Language brought by Laurent Clerc, and various home-grown sign languages used by deaf students from other towns.
Over time, other regional influences blended and evolved into what is known today as the American Sign Language (ASL).
By the late 19th century, transportation improved and island residents began migrating and having children with people from the mainland. The genetic trait responsible for the high rate of deafness gradually declined, and the unique signing island community disappeared.
Independent Linguistic Systems
One of the most common misconceptions about sign languages is that they represent spoken language through gestures. In fact, sign languages are independent linguistic systems with their own vocabulary, grammar, and structure. They do not render their spoken counterparts word-for-word. Instead, they have lighter “word” density, but organize meaning through a layered system of simultaneous elements: hand shape, movement, location, orientation and facial expression. You’ll see a few examples shortly.
Facial expressions, head movements, and body postures function as core grammatical markers. Raised eyebrows can signal a yes/no question, furrowed brows often mark WH-questions (who, what, where, when, why, which and how), and head movements can indicate negation or emphasis, and substitute intonation and punctuation in spoken languages. Body movements indicate things like position or who is talking. These features occur in symphony with the manual signs, creating a multi-layered grammatical system.
Because sign languages use visual cues and space instead of sound, their grammar often develops in ways that differ significantly from its general populations’ spoken languages.
How ASL Resembles Mandarin Chinese
An interesting example of the difference from its spoken counterpart is how the structure of American Sign Language resembles that of Mandarin Chinese.
Example:
“I bought a book and read it.”
English typically follows a Subject-Verb-Object pattern:
English: I bought a book.
ASL tends to use a Topic–Comment structure, where the topic of the sentence is introduced first and then information about it follows:
ASL: Book – I buy.
Mandarin Chinese often also follows the Topic-Comment pattern, where the topic is introduced first with a comment describing what happened to it after:
Hanzi: 这本书，我买了。
Pinyin: Zhè běn shū, wǒ mǎi le.
Literal translation: (This) book, I bought.
Both languages rely heavily on context. Unlike in spoken English, once the topic of the conversation was introduced in ASL, there is no reason to reintroduce it. The “listener” already knows what is being discussed. The signer refers back to the book simply by pointing to its location or whatever movement was used to establish its presence, and then sign:
I – read.
A Mandarin speaker will say it like this:
Hanzi: 看了。
Pinyin: Kàn le.
Literal translation: I/me read (it).
Neuropsychological Aspects
From a neuropsychological perspective, sign languages engage the same core language networks in the brain as spoken languages, particularly areas in the left hemisphere such as Broca’s area and Wernicke’s area. This demonstrates that human language is fundamentally a cognitive system, and not something tied exclusively to speech.
However, sign language processing also recruits regions associated with spatial cognition and motion processing, reflecting the visual modality of the language. Research in neuropsychology and cognitive neuroscience shows that signers often develop strong abilities in visual attention, spatial memory, mental rotation and tracking movement in space.
These abilities are useful because sign languages rely heavily on visuospatial organization and simultaneous visual information. They organize meaning through iconic visuals and spatial relationships instead of sound.
Spatial structure is part of grammar. A signer may establish people or objects in locations around the signer’s body.
For example:
Person A → left
Person B → right
Later in the conversation, the signer simply points back to those locations to refer to them again, or if the signer is paraphrasing Persons A and B, s/he may move into those locations to emphasize who is speaking.
This spatial indexing also functions similarly to pronouns in spoken languages.
Together, these findings reinforce an important principle: human language is modality-independent. Whether expressed through sound or through visual space, the brain organizes language using the same underlying cognitive architecture.
Comparing Signs Used Around the World
Although sign languages are independent languages with their own grammar and vocabulary, some everyday expressions can be compared across systems to illustrate both shared visual logic and linguistic diversity. Using American Sign Language as a baseline makes these comparisons easier to understand.
In all sign languages, pointing is done with the index finger. Linguists call this deixis or indexing. Indexing functions as a pronoun system.
Below are several simple phrases that highlight how different sign languages structure the same idea. Please note that the illustrative representations of common expressions below vary by language, region, and context.
Example 1: “I love you.”
American Sign Language (ASL)
In ASL, the sign for this phrase is a single sign and is particularly famous because it combines three letters – I + L + Y – from the American manual alphabet.
The “you” sign has become a global pop-culture symbol, but linguistically it belongs to ASL.
The chest is universally associated with feelings, hence many sign languages independently developed heart-centred gestures for love, affection and sincerity.
Most other sign languages express this phrase with three gestures:
British Sign Language (BSL)
These variants typically express the phrase sequentially, although “love” can be expressed by arms crossing the chest or hand over the heart, and pointing outward to “you” either with an index finger or with the whole hand.
ME + LOVE + YOU
point to chest + arms cross chest + point outward
French Sign Language (LSF)
Very similar structure as BSL and it is also shared in Brazilian, Dutch and other variants.
ME + LOVE + YOU
point to chest + hand over heart + point outward
Japanese Sign Language (JSL)
The Japanese word for “love” (愛 / ai) and the sign-language gesture actually connect to very old East Asian metaphors about the heart and mind being the same concept.
In Japanese communication, expressions of strong affection are often less direct than in some other countries and softened, and this cultural tendency appears in signing as well. Because of this, the sign corresponding to “like” frequently carries the meaning that foreigners might interpret as “love”, especially in interpersonal contexts. However, the sign for “love” often involves a firmer contact with the chest and a stronger facial expression.
ME + LIKE + IT/YOU
point to chest + open hand on chest with slight outward movement + point outward
Example 2: “Hello”
American Sign Language (ASL)
open hand near the temple → (optional: move outward slightly)
The hand is open with fingers together, palm facing outward, and touches or hovers near the temple, then moves outward slightly away from the head. Conceptually, this mirrors a casual spoken greeting like “hi.”
British Sign Language (BSL)
The “hello” greeting is often closer to a small wave.
open hand → small outward wave
The palm faces outward, the hand is held near shoulder height, and a small side-to-side motion signals the greeting.
French Sign Language (LSF)
The “hello” sign often uses a gesture near the mouth.
fingers together near mouth → move outward
The fingertips begin near the lips, the hand moves forward and slightly outward, and the palm rotates outward as it moves.
Egyptian Sign Language (ESL)
Arabic language family signs vary by Arabic language variety.
he greeting typically references the spoken greeting “salaam.”
flat hand touching chest → slight outward movement
The right hand touches the chest, then the hand moves outward slightly, and the facial expression usually conveys warmth. The gesture reflects the cultural greeting meaning “peace.”
Japanese Sign Language (JSL)
The greeting often resembles a small bow combined with a hand gesture.
open hand near the side of the face → slight downward motion
The hand begins near the cheek or nose, then a small downward or outward motion accompanies the greeting, often paired with a slight bow. This reflects Japanese greeting etiquette.
Brazilian Sign Language (LIBRAS)
A common greeting resembles a casual wave.
open hand near forehead → small outward wave
The palm faces outward, the hand begins near the forehead and a small outward motion signals greeting. This gesture is similar to greetings used in several Latin American sign languages.
Even though sign languages are not universal, greetings often look similar because they reflect natural human gestures for acknowledging another person.
The International Sign Language
How do Deaf people communicate internationally?
The closest thing to a universal sign language is International Sign (IS), which developed naturally over time through repeated interactions among signers from different linguistic backgrounds.
International Sign is not anyone’s native language, nor is it standardized. It is best described as a contact system that has evolved through decades of international interaction within the global Deaf community. It is widely used at events organized by organizations such as the World Federation of the Deaf and the International Committee of Sports for the Deaf.
Instead of relying on the vocabulary of a single national sign language, International Sign emphasizes communication through signs that are broadly understandable. Signers naturally adapt their language by choosing highly iconic signs from across sign languages, simplifying grammar where appropriate, and using shared visual strategies such as images, pointing and facial expressions to negotiate meaning.
Interactions vary, depending on the background of the signers. This often allows people with very different linguistic backgrounds to understand one another surprisingly well.
While International Sign works well for everyday conversations, conference presentations, and travel, it is not intended to replace national sign languages. Discussions involving medicine, law, science, education, or other specialized subjects generally require interpreters fluent in the relevant national sign languages.
In this sense, International Sign occupies a role similar to English in international communication. It is the global lingua franca for Deaf people. It provides a shared medium that allows people from different countries to express themselves and to share their thoughts and ideas.
Range of Communication and Limits
Like spoken languages, sign languages are capable of expressing virtually any human thought. They can communicate abstract ideas, tell stories, convey humour, discuss philosophy, teach science, debate politics, express emotion, and support everyday conversation. They are complete natural languages with rich vocabularies and sophisticated grammars.
One of their greatest strengths is their engaging visuospatial expressiveness. While spoken languages organize meaning through sound, sign languages organize it through handshape, movement, location, palm orientation, facial expression, eye gaze, and body position. Several of these features often occur simultaneously: the hands carry the main action while the face marks a question, the body signals perspective, and the signing space keeps track of the people or objects being discussed. In noisy environments, spoken conversation may become difficult, but signing remains effortless. A spoken-language speaker can communicate the same information, but mainly with words; sometimes with some animation to add spice.
That same visuospatial nature, however, also introduces practical limitations.
Unlike speech, signing requires continuous visual attention. Communication becomes difficult in complete darkness, when visibility is low or obstructed. Maintaining eye contact is therefore a fundamental part of signed communication, whereas spoken conversation can continue while people face different directions or even speak to each other on the phone without video.
Signing also occupies the hands. While experienced signers naturally adapt, activities that require continuous manual control—such as carrying objects, handwork, or driving—can limit the ability to sign and limit signers to certain types of jobs and hobbies.
Technology has helped overcome some of these constraints. Video calling has transformed communication within Deaf communities by allowing signers to converse naturally over long distances, something that traditional telephone networks could never provide. High-resolution cameras, faster internet connections, and smartphones have made signed communication available almost anywhere.
At the same time, technology has highlighted the complexity of sign languages. Automatic sign language recognition remains significantly more challenging than speech recognition. AI systems must interpret not only handshape and movement, but also palm orientation, facial expressions, eye gaze, body posture, timing, and the use of three-dimensional space. Small differences in any of these features can change grammatical meaning.
AI translation for sign languages is still in its early stages. While impressive progress has been made in recognizing isolated signs and generating signing avatars, accurately translating natural conversations remains an active area of research.
If you’ve missed previous editions of the Santium Language Series, you’ll find them here – catch up!
How Santium contributes to this space
Santium provides specialized translation and cross-cultural research services focused on adapting and validating scientific, medical and technical content. We deliver translated materials that work as intended across languages and cultures through translation, linguistic validation, and subject-matter specialist engagement, preserving meaning, functionality, usability, and, where applicable, measurement integrity in real-world applications and settings.
Follow Santium to stay connected
If you found this article interesting, follow me on LinkedIn and join our newsletter to receive future editions. In the Santium Language Series, I explore interesting traits of the world’s languages, from the most widely spoken to obscure, introducing their structure and word formation to cultural nuance and their role in social norms.
Stay connected and don’t miss the next edition!
References
The Signs of Language. (1979). The signs of language. Harvard University Press.
David F. Armstrong, William C. Stokoe, & Sherman E. Wilcox. (1995). Gesture and the nature of language. Cambridge University Press.
Karen Emmorey. (2002). Language, cognition, and the brain: Insights from sign language research. Lawrence Erlbaum Associates.
Trevor Johnston, & Adam Schembri. (2007). Australian Sign Language (Auslan): An introduction to sign language linguistics. Cambridge University Press.
William C. Stokoe. (1960). Sign language structure: An outline of the visual communication systems of the American Deaf. Studies in Linguistics, Occasional Papers No. 8.
World Federation of the Deaf. (n.d.). International Sign. https://wfdeaf.org
Ethnologue. (2025). Languages of the world: Sign languages. SIL International. https://www.ethnologue.com
World Health Organization. (2021). World report on hearing. World Health Organization.
United Nations. (2006). Convention on the Rights of Persons with Disabilities. United Nations.
Gallaudet University. (n.d.). Visual Language and Visual Learning Science of Learning Center. https://www.gallaudet.edu
Monika Vance
Managing Director | SANTIUM
My work sits at the intersection of linguistics, scientific and medical translation, psychometric measurement, and multilingual operations, where terminology, usability, and regulatory context must align. I write about scientific and medical translations, psychometrics, languages, and the operational challenges that inevitably come with them. I also teach translators how to properly translate and validate complex psychometric instruments to hone their expertise in linguistic validation.
