How Can I Switch Synthesizers on the Fly?

[Chime Hart <chime@xxxxxxxxxxxxxxxxxxx>]

Hi All: I've asked others in other forums such as Slint-and-Debian 
Accessibility, but so far I am striking out. I have a DecTalk U S B, but last 
year I purchased some hi quality voices from Oralux, which are software speech. 
When I have Allison installed, I can send her text through spd-say. Making 
matters more complex, speech-dispatcher will not seem to install on this Debian 
Sid machine. Guidance I've received from 2 sources, says I must install and 
have espeak talking before I can switch to Allison, which is an embedded voice. 
When I was running Slint on a laptop, Didier had created a talk-with command to 
easily switch synths, but his script would need to be re written for Debian. In 
addition, 
if I unload the DecTalk module, I won't have speech, or would their be a way of 
having both DecTalk and software speech at the same time? So, can some1 please 
provide exact commands I can switch synths on the fly? I ran a locate for 
softsynth  but nothing found. Thanks so much in advance
Chime