Plain Language Association InterNational (PLAIN)

A volunteer non-profit organization of plain-language advocates, professionals, and organizations committed to plain language. PLAIN has an email discussion group you can join. You’ll find links to plain-language resources, government initiatives and other organizations in many different countries through PLAIN’s home page. 
http://plainlanguagenetwork.org/

Clarity

A worldwide group of lawyers and interested lay people. Its aim is the use of good, clear language by the legal profession; its twice-yearly journal includes articles relevant to plain language in other fields. 
http://www.clarity-international.net/

Statute Law Society

A charitable UK-based body that aims to educate the legal profession and the public about the legislative process, and the structure and drafting of statute law. 
http://www.statutelawsociety.org/index.html

Center for Plain Language

The Center for Plain Language, a non-profit organization, wants government and business documents to be clear and understandable. It supports those who use plain language, trains those who should use plain language, and urges people to demand plain language in all the documents they receive, read, and use.

http://www.centerforplainlanguage.org/