When was written language developed?

It's impossible to pinpoint an exact date for the development of written language, as it evolved gradually over thousands of years. However, we can look at some key milestones:

* Around 3500 BC: The earliest known writing systems, cuneiform in Mesopotamia and hieroglyphs in Egypt, emerged.

* Before 3000 BC: Proto-writing, which predates full writing systems, began to appear in various cultures, using symbols to represent specific ideas or objects.

* 3000-2000 BC: Writing systems developed rapidly in different parts of the world, including the Indus Valley, China, and Mesoamerica.

Therefore, while 3500 BC is considered a crucial turning point, it's important to remember that writing likely developed over a much longer period, possibly starting as early as 8000 BC.

There are ongoing debates and discoveries that continue to refine our understanding of written language's origins.