Glossary · Accessibility term
Plain language
Plain language is writing that lets somebody find what they need, understand it the first time, and act on it. That is the international standard's own definition, and the important part of it is what it measures. It is about how successfully a reader can use the document rather than about any mechanical property of the text. A readability formula is a tool for that and never the test itself, which is roughly where W3C leaves it. Its current pages name no particular formula and its technique for this simply says a readability formula is applied. WCAG's own reading-level rule sits at Level AAA, so most sites carry no WCAG obligation for their body copy, and it shows. Other rules can still reach it, and so can a plain-writing duty attached to a sector or a contract, which is worth checking before you assume nothing applies. This is the first thing teams drop, and the accessibility work that needs attention more than it needs budget. It is not entirely optional under WCAG either. The Level A rules asking for labels, instructions and error messages a person can act on cover exactly the text where clear words matter most, which is also where W3C says to start.
In practice
Start where it does the most for the least, which is not the body copy. W3C's own advice is to begin with headings, labels, navigation, instructions and error messages, because those are short and they are what people act on. On most sites that is a small enough body of text to work through in a sitting. Start there.
The concrete guidance has numbers attached and they are usable. Sentences no longer than about 25 words in English. No more than two conjunctions in one sentence. One topic per paragraph. Present tense and active voice, so the sentence says who does what. And put the aim of the sentence at the beginning, which is the same instruction as answering first and explaining second.
The most testable target in the whole area is a vocabulary one. Work from the most common 1,500 words, because those are the terms people with severe language impairments are most likely to know. Then the rule product teams break constantly. Do not invent words, and do not give an existing word a new meaning inside your interface, because nobody is going to learn your vocabulary just to use your product.
One thing about the WCAG rule itself, because it gets quoted wrongly. The reading-level criterion is written in years of schooling rather than in years of age. It asks whether text needs reading ability beyond the level expected at the end of lower secondary education. Where it applies, the example W3C gives of measuring it is a qualified teacher reading the text against local education standards. A tool can help you get there and it cannot answer the question for you.
Why it matters
The human reason is about effort rather than intelligence. Reading disabilities make it hard to recognise a written word and match it to its sound. That decoding has to become automatic before anybody reads fluently. Doing it word by word eats most of the attention a person would otherwise spend on understanding what they read. Hard words do not only slow that reader down, they use up the budget. The objection to head off is the one about audience. Difficult writing can suit most of the people it is aimed at. There are still people with reading disabilities inside any group of highly educated specialists. So our readers are all professionals is not the answer it sounds like.
One word, real harm
W3C's own example is a heating and air conditioning unit whose menu item for choosing heat or cooling is labelled Mode. Somebody with mild dementia cannot get past it, and cannot use the unit at all because of that one word. The document records that this kind of design has caused emergencies including hypothermia. Nothing about the interface was broken. One word was chosen by somebody who already knew what it meant.
Where this shows up on the site
Related terms
- Cognitive disabilityCognitive disability is a broad group of conditions affecting how people take information in, hold on to it, and act on it.
- DyslexiaDyslexia is a set of processing difficulties that affect the acquisition of reading and spelling.
- UnderstandableUnderstandable is the third of WCAG's four principles, and it splits in two the way its own sentence does.
- Error identificationError identification is the Level A rule that when your form rejects something, the page names the field that failed and says in text what went wrong.
Knowing the word is the easy part.
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