Yes, sign language differs significantly from country to country. There are over 300 distinct sign languages used around the world, each with its own vocabulary, grammar, and structure. Sign languages are not universal, and they are not simply signed versions of whatever spoken language surrounds them. Two countries that share a spoken language, like the United States and the United Kingdom, can have completely different sign languages.
Why Sign Languages Are Independent of Spoken Languages
One of the most common misconceptions is that sign languages are visual codes for spoken languages. They are not. Linguistic research has consistently shown that sign languages used by deaf communities are fully developed human languages, independent of the spoken languages in the same region. They have their own grammar, syntax, and rules for forming words and sentences, none of which are borrowed from the local spoken language.
This independence is why American Sign Language (ASL) and British Sign Language (BSL) are mutually unintelligible, even though both countries speak English. ASL actually has more in common with French Sign Language than with BSL, because of how it developed historically. Meanwhile, countries that speak completely different spoken languages sometimes share a sign language or closely related ones. Croatian and Serbian sign languages, for example, are considered the same language, and Indian and Pakistani sign languages are closely related enough that researchers debate whether they are one language or two.
How ASL and BSL Illustrate the Differences
The contrast between American and British sign languages is the clearest example of how national sign languages diverge. The most immediately visible difference is the manual alphabet: ASL uses a one-handed fingerspelling system, while BSL uses two hands. In BSL, vowels are made by pointing to the thumb and four fingers, and most other letters require both hands. In ASL, the entire alphabet is produced with a single hand.
The grammar is fundamentally different too. ASL uses a topic-comment structure, where you introduce the subject first and then elaborate on it. BSL follows a subject-verb-object order more similar to spoken English. The vocabulary is almost entirely different. An ASL signer placed in a room full of BSL users would not be able to follow the conversation without training in BSL, and vice versa.
How History Shaped Sign Language Families
Sign languages have family trees, just like spoken languages. The reason ASL resembles French Sign Language traces back to a specific moment in history. In 1817, Thomas Hopkins Gallaudet and Laurent Clerc, a deaf educator from the Institut Royal des Sourds-Muets in Paris, co-founded the American School for the Deaf. Clerc brought French Sign Language with him, and it merged with signs already in use among American deaf communities. Legend has it that on the ship crossing the Atlantic, Gallaudet taught Clerc English while Clerc taught Gallaudet sign language.
That French connection created a large language family. French Sign Language gave rise to or heavily influenced ASL, Dutch Sign Language, Italian Sign Language, Belgian Sign Language, and others. BSL, which developed independently in Britain, spawned its own family: Australian Sign Language (Auslan), New Zealand Sign Language, South African Sign Language, and Northern Ireland Sign Language all descend from Old British Sign Language dating back to around 1760. These related languages within the same family share more vocabulary and structure with each other than with languages from a different family.
Countries That Share a Sign Language
National borders and sign language borders don’t always line up. The United States and English-speaking Canada both use ASL, which is officially recognized in Canada through the Accessible Canada Act. Auslan, New Zealand Sign Language, and BSL are similar enough that signers from these countries can often understand each other reasonably well, though differences have grown over time. Paraguay and Uruguay share closely related sign languages, both descended from Old French Sign Language.
Linguists generally consider two language varieties to be the same language when speakers can understand roughly 70% or more of each other’s vocabulary. Below that threshold, they are typically classified as separate languages. Many national sign languages fall well below that line when compared to each other, making them distinct languages rather than dialects of one global system.
How Deaf People Communicate Internationally
When signers from different countries meet, they often use what is called International Sign. This is not a formal language with fixed grammar and vocabulary. It is a contact system, meaning it emerges naturally when signers from different backgrounds interact. The specific form it takes shifts depending on the language backgrounds of the people in the room.
International Sign is commonly used at events organized by the World Federation of the Deaf, at international sports competitions for deaf athletes, and at other cross-border gatherings. It draws on highly iconic gestures, mime, and shared elements from various national sign languages. However, it has never developed into a full language the way ASL or Dutch Sign Language have. Its use remains limited to formal international settings, and no deaf community uses it as a primary everyday language.
No Standard Written Form
One factor that reinforces differences between national sign languages is the lack of a widely adopted writing system. Spoken languages can be learned and standardized partly through written text, but sign languages have no equivalent written tradition. Notation systems exist, including Stokoe Notation (developed in the 1960s) and Sutton SignWriting, but neither has achieved widespread daily use in any deaf community. Without a shared written form, sign languages evolve and diverge locally, much the way spoken languages did before widespread literacy.
This means that sign languages are primarily passed down through face-to-face interaction, in deaf schools, deaf clubs, and families. The result is rich local variation, not just between countries but sometimes between regions within the same country, with distinct dialects emerging in different cities or schools.