The free nationwide telecommunications relay service (TRS), reached by calling 7-1-1, uses communications assistants (also called CAs or relay operators) who serve as intermediaries between people who have hearing or speech disabilities who use a text telephone (TTY) or text messaging and people who use standard voice telephones. The communications assistant tells the telephone user what the other party is typing and types to tell the other party what the telephone user is saying. TRS also provides speech-to-speech transliteration for callers who have speech disabilities.
Luckily, the international nonprofit World Wide Web Consortium (W3C) brings together smart people who develop open standards to ensure the long-term growth of the Web. They produce recommendations for making websites fair and equally accessible for the highest number of people possible. Their Web Content Accessibility Guidelines (WCAG) 2.1 offer clear guidance for web developers to achieve ADA compliance.
@Rick, I didn't specifically look at doctype, but Steve Faulkner did in his original article (see the link at the top of this post). He found that 101 of the 130 pages containing role="main" (78%) used the HTML5 doctype, which of course leaves 22% that didn't. I do recommend using ARIA even if using an earlier doctype. Validation is important, but if validation and accessibility conflict, I think most would agree accessibility should trump validation. Assistive technologies that support ARIA landmarks do so regardless of doctype, and otherwise the presence of these role attributes has no ill effects in any user agent.
For people who have speech disabilities, this may include providing a qualified speech-to-speech transliterator (a person trained to recognize unclear speech and repeat it clearly) , especially if the person will be speaking at length, such as giving testimony in court, or just taking more time to communicate with someone who uses a communication board. In some situations, keeping paper and pencil on hand so the person can write out words that staff cannot understand or simply allowing more time to communicate with someone who uses a communication board or device may provide effective communication. Staff should always listen attentively and not be afraid or embarrassed to ask the person to repeat a word or phrase they do not understand.
Another important consideration is that the ADA does not allow businesses to simply provide an alternative such as a phone number. Lastly, include accessibility issues as part of your website and mobile strategy. When new technologies are implemented or pages added, part of the process should include the implications for persons with disabilities. 
The Justice Dept. said it would issue new regulations, so most businesses waited to see what they would say. However, Vu believes it will be a while before the new regulations are released because of what the Justice Dept. said in a recent case. MIT and Harvard were sued over captioning of videos, and the schools wanted the judge to stay the case until the new regulations were released. The Justice Dept. told the judge not to stay the case because the new regulations could take a while to be released.
Upon discovering issues faced by disabled government employees and the public, revisions to section 508 were made. The issues that were uncovered involved websites, documents, and software programs. As of January 2018, the updated 508 standards require all federal agencies and contractors to create web content accessible to all. The updated standards also include Website 508 compliance.
It’s an important tool because Contact Form 7 isn’t so accessible by default. The plugin adds a selection of accessible form types to use as the basis for your new form. Note that it doesn’t affect pre-existing forms – just new ones. For existing forms, you’ll have to recreate them using the new templates. That’s why it’s recommended that you install this companion plugin on your site at the same time as Contact Form 7.
The ADA requires that title II entities (State and local governments) and title III entities (businesses and nonprofit organizations that serve the public) communicate effectively with people who have communication disabilities. The goal is to ensure that communication with people with these disabilities is equally effective as communication with people without disabilities.