1. How do I connect to a sound card?

2. After connecting I wanting to send signals there how do I do that?

3. What is the format of the signals that I send have to be in?

I know I can use windows api's to acheive all of this more easily, but I want to see if it is possible to take a sound such as a person saying "a" and making it say anything by changing the frequency adding and changing things.

Thanx in advance!