If you want even older technology (that actually worked rather well) there's Votrax,
which apparently is still available occasionally.
paul
On Jul 26, 2018, at 1:38 PM, Anders Nelson via cctalk
<cctalk at classiccmp.org> wrote:
It takes 9600 (8N1) serial input, and I found a forum thread:
http://www.vcfed.org/forum/archive/index.php/t-34754.html
"The DECTalk was a speech synthesizer (actually there were a few models).
The DTC01 and 03 can do text to speech when fed ascii text over RS232."