Tim,
Just a simple delay should work fine for you. I don’t use SoundForge or Vegas so I can’t tell you specifics, but I would do it by either:
1) route your delay as a send effect through your virtual mixer and just boost the delay send for the last syllable. This would be a non-destructive way of editing and I don’t know if it applys to SoundForge.
Or
2) you can splice or isolate your the last syllable of your sound file and just apply a delay effect to that which would be a destructive way to edit but might be just fine for what you want to accomplish.
Hopefully someone with SoundForge knowlege will jump on here to give you some specifics.
Best of luck.
Cheers.
– Scott
Scott McAuliffe
Urchin Multimedia Design
http://www.urchinmultimedia.com
http://www.pbase.com/smcaulif