From what I've been able to gather around the web, it seems that it was a variant of the Covox Speech Thing marketed by Coktel Vision. A bunch of their games, including "Fascination", support it, and their manuals also advertise it.
As for the CST, it was a crude sound device developed in the late 80s, before soundcards in PCs became common. It plugged to the printer port and a bunch of games support it:
https://en.wikipedia.org/wiki/Covox_Speech_Thing