I watched a YouTube video one day about how you could get the talkbox sound with headphones and a computer. This is very cool.
Things you'll need:
Earbuds/Apple headphones (Can't use the ones that wrap around your head unless you have a huge mouth)
A computer with Internet access
Put your headphones in.
Go to www.angryoctopus.co.nz/synth8.
Step 3: How It Works
Place the earphones together like the picture above and place them in your jaw and use the synth and mouth words without actually talking as you play it. Hope this helps! ;) And don't forget to turn the volume on your computer all the way up!