Here's why:
* Natural Communication: Sign languages are natural forms of communication that arose from the need for people with hearing impairments to communicate.
* Independent Development: Different sign languages developed independently in different parts of the world, just like spoken languages.
* Not a Single Language: There isn't one universal sign language. There are hundreds of sign languages, each with its unique grammar, vocabulary, and regional variations.
When did sign languages develop?
It's impossible to pinpoint an exact date, but it's likely that sign languages have existed for centuries, if not millennia. Evidence suggests that:
* Ancient Civilizations: Sign languages were likely used in ancient Egypt, Greece, and Rome.
* Deaf Communities: Deaf communities have always existed, and they would have developed ways to communicate with each other.
Key Milestones:
* 18th Century: Formal education for the deaf began in Europe, and sign language schools were established. This led to standardization of some sign languages.
* 19th Century: The development of sign language dictionaries and grammars further formalized sign languages.
* 20th Century: Sign language research began to flourish, and the linguistic richness of sign languages was increasingly recognized.
In conclusion:
Sign languages are not inventions, but rather natural, organic forms of communication that evolved over time. They are diverse and fascinating, reflecting the richness and ingenuity of human communication.