If we go back in history what is the earliest form of communication that would have been scalable?

I could think of "writing" and "Paintings"

Paintings suffer from a problem which is context, unlike writing.

When writing as a communication medium began, asynchronously lot of people would have access to knowledge an older group of people experienced.

For Example:

The below one in tamil was written some 2000 years ago by Thiruvalluvar with 7 words. Its meaning can change anyone who reads it.

தெய்வத்தான் ஆகா தெனினும் முயற்சிதன்

மெய்வருத்தக் கூலி தரும்.

It's meaning:

Even though God be against it, Effort is bound to pay the wages of labour.