Are there any vocal chord experiments that attempt to synthesize communication externally? I have an idea for an experiment.  Basically, the experiment would be to create a novel transmission of visual information via the human vocal chords, but not as a traditional human spoken language per se.  

The vocal chords are first trained by an external instrument to produce a specific pattern that is associated with an image such as a simple circle.  In addition, a "listening" machine is calibrated to process the sounds emanating from the vocal chords.  

At first, this doesn't sound so different than language as we use it now and how we interact with voice-recognition technology such as Siri, but what if the vocal chords were trained to produce patterns an order of magnitude more quickly than what is currently achievable?  The current world record for speaking is 637 words per minute or 10 words per second.  

Also, the patterns that I am thinking of would completely bypass our language processing centers and be immediately received by our visual cortex (or something like that).  After all, a picture is worth a thousand words.

So, are there any vocal chord experiments that attempt to synthesize communication externally or come anywhere close to what I am proposing?
I have studied computational neuroscience, first as an undergraduate at the University of Chicago, and then as a graduate student at UCSD and the Salk Institute.

As an answer to your question, to my knowledge, and after a quick search on google scholar, there are no studies that try to reroute auditory information to the visual cortex through the vocal chords. 

And I wouldn't imagine there would be. Auditory (cochlear, thalamic and cortical) and visual (retinal, thalamic and cortical) processing centers  are highly optimized for different flavors of information. Visual information is higher band-width, continuous along multiple dimensions, and relies on many parallel filters and aggregators. Auditory information is serial, and recursive.

Here's some information that might help you get to the heart of your inquiry. First, take a look at neural prosthetics in general. These facillitate information delivery directly to the nervous system, bypassing sensory input:
http://en.wikipedia.org/wiki/Neuroprosthetics

For a look at sensory modality switching, take a look at delivering visual information through tongue stimulators (work pioneered by an interesting researcher named Paul Bach-y-Rita):

Finally, take a look at an experiment in which visual information is sent to the auditory cortex, by way of thalamic surgery in ferrets, if I have my citation correct. The auditory cortex proved to be able to adapt to the visual information by forming some structural characteristics of the visual cortex:
http://www.nature.com/nature/journal/v404/n6780/abs/404841a0.html

Perhaps the most interesting part of that last link, in terms of your inquiry, is that the visual information did not bypass auditory processing centers. It transformed them.