WCAG Principles: Understandable

People with disabilities must be able to understand your content and 0:00 use your interfaces. 0:05 The Understandable principle is broken into three guidelines, 0:08 beginning with one called Readable. 0:13 The level A requirement is pretty simple: developers should set an appropriate 0:15 language attribute so screen readers know what language to expect and 0:21 what accent to use in pronouncing page content. 0:26 In the example shown here, the document's primary language is English, but 0:31 this particular paragraph asks the screen reader to switch to French pronunciation. 0:37 The Readable guideline also covers plain language. 0:46 The website plainlanguage.gov, a resource for keeping body copy clear and 0:49 straightforward on federal government websites, 0:56 recommends using strong, simple words, short paragraphs, 1:00 clearly organized information, and a conversational tone. 1:06 I'm looking at a sample of complex versus plain language. 1:14 The lengthy single paragraph on the left creates an intimidating 1:20 wall of words that few would enjoy reading. 1:25 And check out this sentence: 1:28 "The fungal material is carried into the respiratory tract when 1:30 airborne particles are inhaled." 1:35 I'm guessing listening to me read that was pretty tedious. 1:38 The presentation on the right delivers the same information, but in clear language. 1:43 Be careful. Watch out for mold in all these materials after a flood. 1:49 Simplifying language like this helps users with cognitive disabilities, low 1:56 reading literacy, and those encountering an unfamiliar topic or language. 2:01 The second guideline, Predictable, has to do with keeping app and 2:08 website experiences predictable and navigation schemes consistent, 2:13 something which benefits all users regardless of physical ability. 2:20 In addition, 2:27 the predictable guideline warns against unexpected changes in context. 2:28 To avoid disorienting users, the following should happen only when 2:35 the user initiates a change by interacting with an interface element: 2:40 opening a new window, loading a new page. 2:46 significantly rearranging page content, or moving focus to a new component. 2:52 As the Mozilla Developer's Network says on the subject, 2:59 people don't want interfaces to surprise them. 3:03 They want things to be intuitive and behave as expected. 3:06 The final understandable guideline is called Input Assistance. 3:13 Users sometimes make mistakes, 3:19 no matter how well designed the web form or interface. 3:21 Prevent frustration by making errors easy to spot and correct. 3:26 A Nielsen Norman group article linked in the Teacher's Notes 3:33 offers three principles for error reporting in forms. 3:38 The error message should be easy to notice and understand. 3:42 The fields in error should be easy to locate. 3:47 And users shouldn't have to memorize the instructions for fixing the error. 3:52 We'll take a closer look at building an accessible form 3:58 in the second stage of this course. 4:02 You might have noticed that the Understandable principle 4:06 was quite a bit shorter than either the Perceivable or Operable principle. 4:09 Our final principle, Robust, is the shortest entry of all in the WCAG. 4:15 We'll take a closer look in our next video. 4:21