It's not a symbol. It's a word. It's pronounced "Yam". The script in which it is written, (Devanagri) isn't that old. The sound "Yam" is older, as old as Yoga itself (at least 5k years back). Sanskrit was written in other scripts as well, so in other scripts it wouldn't look like यं.

And before that it was an entirely oral language.

It's not a symbol. It's a word. It's pronounced "Yam". The script in which it is written, (Devanagri) goes all the way back to Maharishi Panini, over 5k years ago. Don't believe the wikipedia date for Panini as it suffers from colonial bias (all of Vedic history in India is compressed into 1000 years in order to fit in with the "Aryan Invasion/Migration Theory"), despite enough literary references to stuff that occurred thousands of years before even the earliest dating of the so called Aryan Invasion/Migration.

It's not a symbol. It's a word. It's pronounced "Yam". The script in which it is written, (Devanagri) goes all the way back to Maharishi Panini, over 5k years ago. Don't believe the wikipedia date for Panini as it suffers from colonial bias (all of Vedic history in India is compressed into 1000 years in order to fit in with the "Aryan Invasion/Migration Theory").