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.

Because of this, among the greatest drivers of website accessibility are usability improvements and the reputation boost that it brings—or, alternatively, the lost business that organizations want to avoid as a result of inaccessible websites. According to a survey by the National Business Disability Council at the Viscardi Center, 91 percent of customers say that they’d prefer to shop at a website that prioritizes accessibility.
Both sites support multiple languages (English and Spanish), and both include lang="es" on the element of the Spanish pages. However, on the CDC site, in addition to lang="es" the element has xml:lang="en". This potentially sends mixed messages to screen readers (is this web page in Spanish or English?) JAWS 13 seems to honor lang rather than xml:lang but I don't know about other screen readers.
The situation has now emboldened many people. She is dealing with tons of demand letters going out across the country. Businesses have been caught off guard because they thought they had time to deal with this and become compliant, and now the Justice Dept. basically says they have to be compliant now. As soon as they deal with one plaintiff, another comes along.
Use the Outline button on the WAVE toolbar to see if the web page has a halfway decent, logical heading structure. I was pleased to see that each of the 130 sites used HTML headings, but several sites had heading creep. Screen reader users benefit tremendously from good heading structure, but if a web page has too many headings, this offsets the benefits, and some of these sites have several dozen headings. If everything is a heading, nothing is a heading.
All public-facing websites should evaluate and consider compliance with ADA laws related to their industry. That is, your website should aim to be accessible to users with a disability. Failure to comply with this requirement can lead to potential legal issues and challenges, particularly in some industries. Fortunately for WordPress site owners, there are at least a dozen plug-ins specially designed to help you achieve greater measures of ADA compliance with minimal costs and work involved. The following are five options to consider to make your WordPress website ADA compliant.
...the full and equal enjoyment of the goods, services, facilities, or accommodations of any place of "public accommodation" by any person who owns, leases, or operates a place of public accommodation. Public accommodations include most places of lodging (such as inns and hotels), recreation, transportation, education, and dining, along with stores, care providers, and places of public displays.
Use the Outline button on the WAVE toolbar to see if the web page has a halfway decent, logical heading structure. I was pleased to see that each of the 130 sites used HTML headings, but several sites had heading creep. Screen reader users benefit tremendously from good heading structure, but if a web page has too many headings, this offsets the benefits, and some of these sites have several dozen headings. If everything is a heading, nothing is a heading.
The ADA statute identifies who is a person with a disability, who has obligations under the ADA, general non-discrimination requirements and other basic obligations. It delegates fleshing out those obligations to federal agencies. The agencies issue regulations and design standards. The regulations have the details on the rights of people with disabilities and responsibilities of employers, state and local governments, transportation providers, businesses and non-profit organizations. The design standards specify how many entrances need to be accessible, how many toilet rooms and the design for those elements.  To know what the ADA requires, you need to read the law, regulations and design standards.  
I should mention one caveat to all of this. Businesses that are required to comply but don't have the ability to bring their websites into compliance can provide an accessible alternative to provide the same information, goods, and services that they provide online, like a staffed phone line. The trick, however, is that this option has to provide at least equal access, including in terms of hours of operation. And, as we know, the internet is around 24/7, so good luck with that. 

Input Assistance: When users are entering input into the website, any input errors are automatically detected and written out, providing, for instance, text descriptions that identify fields that were not filled out or data that was in the wrong format. The website also provides suggestions to fix the errors. Input fields and buttons are labeled to provide their functions and instructions. If the user’s input is being used for legal purposes or financial transactions, then the user must be able to reverse submissions or correct errors.
Most recently, however, pizza chain Domino's has been brought under suit for their website not being accessible for specialty ordering. The U.S. Supreme Court refused to review the case, instead upholding the decision of the 9th U.S. Circuit Court of Appeals who said the “alleged inaccessibility of Domino’s website and app impedes access to the goods and services of its physical pizza franchises—which are places of public accommodation.”
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. 
A language picker at the top of the page. When users select a new language, the page is reloaded with all text translated. The lang attribute on the element also changes to reflect the new language, so screen readers will pronounce the text correctly. This is a very cool feature, and makes the site accessible to millions of people who would otherwise be excluded due to language. However, it's a little buggy. Selecting some of the languages (e.g., " Slovenčina") does not result in translated text on the home page, but does result in a changed lang attribute, so screen readers that support the selected language will pronounce the English text using the new language's speech engine, which is not likely to be intelligible.
Talk to your web designer about other techniques that will make your site more user-friendly for people with disabilities. Worried that’s not in your budget? Consider the fact that DOJ fines start at $75,000. And it's still yet to be determined if a non-compliant website is liable for one fine or will be charge per page for each violation. As the recent lawsuits illustrate, though, settlements quickly add up into the millions.
Up-to-date standards are offered for checking compliance, and it provides a cost-effective way to scan a site for compliance. There's services out there where it'd cost more than $150 (the current cost of a 1 site 1 year license) for the size of the sites I'm working with. I'm very happy to see this offering in the first place, and it's even nicer to see how thorough it looks to be. Of course, it's not perfect so I'd love to see more of the listing fleshed out (the developer author/contributor mention is missing, etc.), I'd love to see the free version on GitHub (or similar for community development assistance [I have a few things I'd help with] which is very nice to see in a listing to show there's support / ongoing development for the plugin), and of course I'd love to see the server-side checker come to feature-parity with WAVE (currently WAVE is showing a few things the server-side checker doesn't have [color contrast, etc.]) Keep up the great work!
Until the ADA is updated to address the special case of website accessibility, or the Department of Justice releases its website accessibility regulations, complying with WCAG 2.0 Level AA is the best way to ensure that people with disabilities have equal access to your website. The overview below is a great starting point about meeting the WCAG 2.0 Level AA recommendations.

“The idea of equal access, equal opportunity has sort of evolved in its application from brick and mortar to eCommerce. At first, many companies were worried about the desktop experience. Now, the concern extends to both smart phones and devices.  Wherever a consumer accesses your content – whether it be directly through the web or an app – you need to be concerned about accessibility.”
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.