Here's why:
* Sign language has existed for centuries, perhaps even millennia. It's a natural form of communication that developed independently in different cultures around the world.
* There is no single origin point for sign language. Instead, various sign languages have evolved over time, adapting to the needs and cultures of Deaf communities.
* Modern sign languages we know today are constantly evolving. They incorporate new signs, incorporate elements of spoken languages, and adapt to technological advancements.
So, rather than trying to pinpoint a specific "invention" year, we can say that:
* Sign language is a dynamic form of communication with a long and rich history.
* Each sign language has its own unique origins and development path.
If you're interested in learning more about a specific sign language, try searching for its history online or consulting with Deaf community members.