I scored one of these on eBay for $20 and have been playing around a bit and discovered it's the same chip used in the AtariVox+ Speech Synthesizer.
I decided to port the PhraseALator application to C#. Part of the process was to change from Mscomm32.ocx to .NET's SerialPort class in the System.IO.Ports namespace.
I made a C# source to PhraseALator available on Github here.