Plain Language: It's the law
President Obama signed the Plain Writing Act of 2010 on October 13, 2010. The law requires that federal agencies use "clear Government communication that the public can understand and use." On January 18, 2011, he issued a new Executive Order, "E.O. 13563 - Improving Regulation and Regulatory Review." It states that "[our regulatory system] must ensure that regulations are accessible, consistent, written in plain language, and easy to understand."
Two other executive orders (E.O. 12866 and E.O. 12988) cover the use of plain language in regulations.
We've written a model plain language webpage for you to use.