And we explained that by saying:

Consistent page layout, recognizable graphics, and easy to understand language benefit all users. In particular, they help people with cognitive disabilities or who have difficulty reading. (However, ensure that images have text equivalents for people who are blind, have low vision, or for any user who cannot or has chosen not to view graphics.)

Using clear and simple language promotes effective communication. Access to written information can be difficult to impossible for people who have cognitive disabilities, learning disabilities, or who are deaf. This consideration also applies to the many people whose first language differs from your own.

So that told us why to use plain language, but didn't tell us what to do or how to do it. In the Web Content Accessibility Guidelines, the what-to-dos are described in a series of checkpoints that accompany each guideline. The checkpoint in this case states:

Use the clearest and simplest language appropriate for a site's content.

I should point out to you that this is a "Priority 1" checkpoint. That means that:

An author must follow this guideline, or one or more groups of users will find it impossible to access information in the document. Implementing this guideline is a basic requirement for some groups to be able to use Web documents.

All governments or organizations that have adopted the W3C's guidelines as their own law or policy at least require compliance with all the Priority 1 checkpoints. The Government of Canada's "Common Look and Feel Policy", for instance, requires all Federal Web sites to be compliant with both Priority 1 and Priority 2 checkpoints by December 31, 2002. The same is true, I believe, for the Government of Ontario.

Unfortunately, during the period we were developing the guidelines - from 1997 through 1999 - we didn't have any plain language professionals involved. We were obviously bright enough to know that plain language was important, but we didn't really know what to tell people. So the best we could say was:

Follow these writing suggestions:

• Strive for clear and accurate headings and link descriptions. Review every heading, outline, and menu to see if the crucial words mean exactly what is intended, and if there are more common words that would convey the same meaning.
• State the topic of the sentence or paragraph at the beginning of the sentence or paragraph.
• Limit each paragraph to one main idea.
• Avoid idiomatic language, technical jargon, and other unfamiliar vocabulary and expressions.