Over 150 sign languages are currently documented. We know there are a lot more—we just don’t know exactly how many. Some estimates range between 350-400. Since so many of these languages are still undocumented, there is a lot of space for you to contribute to the global effort to study these languages and serve the communities that sign them. But why is the exact number so uncertain? Here are some of the factors that linguists have to consider when counting sign languages:  

Documentation Difficulties

There’s a dearth of systematic, academic documentation on world sign languages. National and regional sign languages are easiest to count because they’re used widely across a country or region and taught in schools. There are around two to three hundred of this kind of sign language.  

But that’s not the only kind to count. There are also village sign languages, which occur in small communities with especially high percentages of deafness. In these places, both Deaf and Hearing people sign to communicate—usually in a language they developed together, rather than a national sign language. Linguists know of around 80 village sign languages, and they discover new ones all the time. They suspect there are several hundred in the world! But we still lack academic documentation of these village sign languages and are relying more on anecdotal evidence. 

Language vs. Dialect

Linguists also have to ask whether two varieties of sign language are distinct languages or just dialects of the same language. It’s not as clear-cut as you might expect! One criterion is whether signers of each variety can understand each other—but even that is a continuum. How bad does communication have to get before we decide that two sign varieties are separate languages? 

Signers Are Great Communicators

Here’s another complicating factor: even if two signers don’t share the same language, they can often still get their points across! It just might take longer than usual. They can do this because 1) many signs resemble the thing they represent and 2) many sign languages use similar grammatical features. So how do we decide whether two signers who can communicate are signing in different dialects, or different languages? One way is to show signer #1 a video in the language of signer #2, and if they have a harder time understanding the video than they would understanding in-person, then the languages are probably distinct. 

Language Transplants

Sometimes educators import a sign language from one country to another. Once deaf children start learning it, they don’t leave it unchanged. They introduce signs that they use with their families. And, like all kids do, they come up with new ways to say things to each other. As they grow up, they keep innovating until the language morphs into something new and distinct. So when has a variety changed enough to be its own sign language? It’s hard to say! 

There’s no solid answer yet about how many sign languages exist in the world. One thing is sure, though—Deaf communities and sign languages are largely under-served. Even national sign languages have a fraction of the resources available to spoken languages. With the Certificate in Sign Language Linguistics, you can prepare to help close that gap.  

Ready to partner with Deaf communities around the world? Explore our Certificate in Sign Language Linguistics and all that you can do with it!