The first two Principles of the WCAG deal with Perception and Operation of ICT, but not whether or not the content can be understood. The Understandable Principle moves the discussion over to the user experience. This guideline also promotes consistent and predictable structural and navigational cues that are independent of context and presentation.
Guideline 3.1 Readable
Make text content readable and understandable.
One of the primary reasons to identify language in ICT is the interaction with a screen reader. Screen readers can read in specified language with correct pronunciation. In addition, users may have preferences set to display languages in typefaces better suited to their presentation.
Guideline 3.2 Predictable
Make webages appear and operate in predictable ways.
When moving from page-to-page or from element-to-element inside of ICT, there should be a commonality and consistency to the order and visual presentation.
- 3.2.1 On Focus (Level A)
- 3.2.2 On Input (Level A)
- 3.2.3 Consistent Navigation (Level AA)
- 3.2.4 Consistent Identification (Level AA)
Guideline 3.3 Input Assistance
Help users avoid and correct mistakes.
This guideline deals primarily with interactive forms. It asks to provide ways to identify errors and correct errors and hopefully avoid them in the first place.
- 3.3.1 Error Identification (Level A)
- 3.3.2 Labels or Instructions (Level A)
- 3.3.3 Error Suggestion (Level AA)
- 3.3.4 Error Prevention (Legal, Financial, Data) (Level AA)