Typically, client side software (Flash, Javascript) don't have access to much client side data such as microphone input. Imagine if you went to Amazon's web site, for example, and they had some Flash on the page that could receive your microphone input - that Flash could upload a copy of what you were saying without you even knowing it.
Java might be able to get access to your microphone but I'm not sure.
As you said, this isn't a PHP question since PHP runs server side and definitely doesn't have access to the user's microphone.
The only way I could think to do this would be to write a program that runs on the user's computer (not in their web browser). If the user agrees to download and install and run the software (a tall request in these days of viruses), then your software could both listen to the microphone and upload the data but (A) that's not a trivial program to write and (😎 you'd have a hard time getting people to trust you enough to install that software on their machines.
