It's a way to write sign languages. Think of like the alphabet, but for hands, movements etc instead of sounds. Now, it may not be obvious that there is a nece

It's a way to write sign languages. Think of like the alphabet, but for hands, movements etc instead of sounds. Now, it may not be obvious that there is a necessity for a writing system for a minority language embedded in a larger community (spoken language), but there are many uses: preservation, digital use, teaching, linguistic study...