When was sign language first invented?

Sign language wasn't "invented" in the way that a new technology or product is invented. It's a natural form of communication that developed independently in different parts of the world.

Here's what we know:

* Sign languages are ancient: Evidence suggests that sign languages have been used for thousands of years.

* They're not universal: Different communities developed their own sign languages, leading to a variety of sign languages around the world.

* They're constantly evolving: Like spoken languages, sign languages evolve over time, with new signs being created and old ones changing meaning.

While we can't pinpoint an exact date for the "invention" of sign language, it's clear that it's a vital form of communication with a long and rich history.