It is possible to use Skype or Google voice to make calls via the computer. There is computer based text to speech software like etriloquist.
The tricky part is if the spud coming out of the computer goes into the computer to the person on the other end.
I think this has to do with your sound card. But, since the software is all free, you can set it up and see how it works.
I am also picturing that you might be able to use a USB audio adapter, split the headphone jack - one side to the headset and one side to the mic input on the adapter? I have never tried this myself, but you can get the USB audio adapter for $3 on Amazon, so not a big expense to try.
Sincerely,
Antoinette Verdone, MSBME, ATP
Owner, Rehabilitation Engineer
ImproveAbility, LLC
Office: 512-522-1705
Cell: 512-497-6026
Fax: 888-501-1009
Address: 3310 W Braker Lane, Suite 300-424, Austin, TX 78758
DARS Provider# 1-274278960-0-000
"One cannot consent to creep when one has the impulse to soar" -- Helen Keller