"The ADA? What on earth could the ADA have to do with a PC making a beep? Well it turns out that at some point in the intervening 25 years, the Win32 Beep() was used for assistive technologies – in particular the sounds made when you enable the assistive technologies like StickyKeys were generated using the Beep() API. There are about 6 different assistive technology (AT) sounds built into windows, their implementation is plumbed fairly deep inside the win32k.sys driver.

But why does that matter? Well it turns out that many enterprises (both governments and corporations) have requirements that prevent them from purchasing equipment that lacks accessible technologies and that meant that you couldn’t sell computers that didn’t have beep hardware to those enterprises."

Source: https://blogs.msdn.microsoft.com/larryosterman/2010/01/04/wh... (search for ADA)

I read that text too and that's what I was thinking when I made that comment