Unfortunately, TurboTax does not currently provide American Sign Language (ASL) services. Communication with your Tax Pro would be via email.
Alternatively, I believe you could use the free, Federally reimbursed Video Relay Service (VRS) for people who use American Sign Language and who also use a webcam and the Internet or a videophone and high-speed Internet access. You will be discussing sensitive financial data, so this may not be the best choice, but it is an option.