In order to be WCAG 2.0 AAA ADA compliant, text on web sites should be written below a 6th-grade level. However, please keep in mind that all websites are only required to meet WCAG 2.0 AA guidelines as a minimum which does not include readability as a criteria.
Below are the common readability, or plain language, errors that Guide will flag and how you can correct them:
If a text block
Is written above a 6-9th grade level
Sentences should be constructed with a less complex structure. Some suggestions would be to use bullet points, make sure all sentences are active sentences, use shorter words and shorter sentences if possible so that it can be well understood.