Guideline 3.1: Make text content readable and understandable.
This guideline helps you ensure that all text content in your site can be properly read by users and assistive technology. It also helps you provide information which is necessary in understanding the text content.
Text normally composes most of the content of a site. When people visit a site, the information contained in headings, paragraphs, and link texts is what they usually look for first. For most people, reading text is very easy. However, it may be a different case for people with disabilities.
For instance, people who use screen readers do not read the text; instead, they listen to it as the screen reader reads it for them. If you do not indicate the direction of the text and its specific language, screen readers may not be able to speak the text correctly. On the other hand, if you include the language of the text in the page and structure the text well, screen reader users will be able to hear and understand the text properly.
Another example: Some users may find it difficult to comprehend the meaning of a word or a phrase in a page. The effect of this situation is magnified if the developer used the word or phrase in an uncommon way or gave it a specialize meaning. To prevent this scenario from happening, developers can provide definitions of terms and expansions of acronyms in the page.
3.1.1: Language of Page (Level A)
The default human language of each Web page can be programmatically determined. (Level A)
Through this success criterion, you can ensure that user agents can correctly present text and other linguistic content in your web pages.
To achieve this, you need to identify the language used in your web pages. This is done by placing on the html element a lang attribute followed by the language value.
A Page that has a specified language enables browsers to properly display the characters in the page. Also, a page whose language is specified enables screen readers to pronounce the text correctly.
3.1.2: Language of Parts (Level AA)
The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text. (Level AA)
This success criterion applies to pages having multiple languages. Through this success criterion, you can ensure that text that is written in multiple languages can be correctly presented by user agents.
To achieve this, you should identify text that has a language different from the default language of your page. Once you have identified the text, you have to specify its language using the lang attribute.
An example: Let us say you have a page whose main language is English. In one of the paragraphs of the page, there is a Spanish word. Specifying the language of that word as Spanish enables assistive technologies to present the word properly. A screen reader will speak the text of the page in English, but once it moves to the Spanish word, the screen reader will change its pronunciation rules and speak the word in Spanish. Similarly, a Braille display will present the characters of the Spanish word correctly.
You do not need to indicate the language when names appear in the text in other languages.
When a word appears in the text which can be functional either in another language, or it is understood in the currently used language, it does not have to be identified either.
3.1.3: Unusual Words (Level AAA)
A mechanism is available for identifying specific definitions of words or phrases used in an unusual or restricted way, including idioms and jargon. (Level AAA)
When the meaning of a word is not obvious, is not understood in its most frequently used context, or requires exact interpretation, provide the word's meaning or definition. You can either use a glossary, provide the exact meaning on a separate page that you can link to, or if it is sufficient, link the word to a dictionary which provides the exact definition.
3.1.4: Abbreviations (Level AAA)
A mechanism for identifying the expanded form or meaning of abbreviations is available. (Level AAA)
When using abbreviations, make sure that you provide the complete word or phrase at least the first time you use the abbreviation. You can either include it in the text, or similar to how you indicate unusual words, you can link it to the full phrase either in a glossary, a separate page, or a dictionary.
3.1.5: Reading Level (Level AAA)
When text requires reading ability more advanced than the lower secondary education level after removal of proper names and titles, supplemental content, or a version that does not require reading ability more advanced than the lower secondary education level, is available. (Level AAA)
More complex text is readable for most people, however, people with reading disabilities can have a hard time comprehending text. For this purpose, either use an easy-to-understand language, which does not require abilities higher than the lower-secondary education, or provide an alternative version with less complexity.
This success criterion is very difficult to measure, especially that the level of difficulty is different in each language, as well as the lower-secondary education is defined differently in each country or region. While generally it refers to nine years of education, it might still vary by region.
A good way to conform with this success criterion is to use simple sentence and content structure.
3.1.6: Pronunciation (Level AAA)
3.1.6: A mechanism is available for identifying specific pronunciation of words where meaning of the words, in context, is ambiguous without knowing the pronunciation. (Level AAA)
When the pronunciation of a word is not obvious and is required to understand content, provide the pronunciation. You can include the pronunciation in the text, or link the word to a recorded sound file.