Up until recently every voice chat application on my computer has worked just fine. Last month, everything suddenly started to sound robotic. This is really aggravating seeing as how I can no longer effectively hear what people are saying. Apparently I sound like normal on the other persons machine.

Basically:

Voice communications now sound robotic, skype, mumble, etc...

My computer is the only one that this has happened to

I have changed the settings on my firewall, even turned it off for a bit, and have increased the transmit and recieve buffers for my ethernet controller

I have even gone so far as to re-install my OS, which is Vista by factory default, this has not helped

I have yet to try a Linux OS and see if the problem is just windows, but I fear it may be a hardware issue.

I can't for the life of me think of what kind of hardware issue would cause something like this.

Any help would be appreciated

Seems like you have tried everything but anything that has to do with troubleshooting your mic <object class="emojione" data="https://resources.enjin.com/1489581540/themes/core/images/emojione/svg/1f635.svg?0" type="image/svg+xml" standby=":dead:">:dead:</object>

Except that my mic works perfectly, everyone I call can hear me just fine, and the windows sound recorder works just fine, and I have tried using 3 different microphones, including the internal one on my computer, and it is not my sound card because videos and music play just fine

I'd say get new speakers and mic

If you tried different OS... this cut down a lot of possibilities.

It's either, the mic, the speakers (Or their cables), the sound card, or the mother board.

I'd try my mic and speakers on another PC first... then start suspecting the sound card..(if its not integrated to your mother board)