This is a single task, though as usual there must be ongoing support and evolution. I was hoping that an app company would respond, but that hasn't happened.
We have built prototypes using landline phones, with great success. In a cellphone, this could become a killer app with wide usage. But if the OS cannot gain access to the audio stream prior to the modem, that's a problem that can only be solved by incorporating the invention in hardware. A possibility, but it requires relationships above my pay grade.
Perhaps we need a consultant, not an app developer...