If you do get sued, if you immediately remediate your website, you may be able to get the lawsuit dismissed on mootness (there’s no longer anything in dispute, i.e. plaintiffs are arguing your website is inaccessible but you’ve already made it accessible). This definitely does not mean you should wait to fix your website but it does mean you may have an out.
For discussion’s sake – while I don’t know the specific nature of your videos, my guess is that they might be demonstrating various techniques or other content in which simply hearing the audio of the video wouldn’t deliver the full context of the content. If making that content accessible is something you’d want to do, you’d likely want to start with a written description of what takes place in the video. Beyond that, high contrast vector images or diagrams showcasing specific parts of the technique would certainly help.
When choosing an aid or service, title II entities are required to give primary consideration to the choice of aid or service requested by the person who has a communication disability. The state or local government must honor the person’s choice, unless it can demonstrate that another equally effective means of communication is available, or that the use of the means chosen would result in a fundamental alteration or in an undue burden (see limitations below). If the choice expressed by the person with a disability would result in an undue burden or a fundamental alteration, the public entity still has an obligation to provide an alternative aid or service that provides effective communication if one is available.
The Federal Communications Commission (FCC) enforces regulations covering telecommunication services. Title IV of the ADA covers telephone and television access for people with hearing and speech disabilities. It requires telephone and Internet companies to provide a nationwide system of telecommunications relay services that allow people with hearing and speech disabilities to communicate over the telephone.