Well, there is wiggle room here. If the disability will directly impact your ability to do the job, it's not covered. For example, someone in a wheelchair can't be hired to drive a delivery truck. If they work in an office, the disability has no impact on the job, so the ADA applies. Same for us. Public speaking is in that wiggle room, speaking to coworkers is covered. This is my interpretation and what I have been advised. (As an environmental planner, I have looked into this a little.)