Hi,
sometimes it's hard to write :)
It can be a good feature with advanced permissions management add a voice recording to topic
Interesting option.
Looks like HTML5 has support for recording from the microphone:
http://stackoverflow.com/questions/6262372/recording-sound-in-browser
A better way would be to 1) make it an addon 2) use either Bing or Google's dictation service. It would add a small microphone next to the input field. It doesn't work on textareas so a little Javascript foo would need to be used to make it look like a textarea but actually be an input field or just have an extra input field that is copied to the textarea. You can see what I'm talking about by using your phone.
Here's an example of what I'm talking about: http://techwelkin.com/how-to-add-mic-speech-input-icon-in-a-textarea
It gets transcribed. You lose all of the features of a forum with pure voice.