Centre for Plain Language – a generally focused website, with some good tips.
The Australian Federal Office for Parliamentary Counsel has a great summary of what plain language is (and why it’s important to use plain language and not just Plain English)
The USA Federal Plain Language website has some good tips for finding plain language and avoiding bad language.
Peter Tiersma’s Language and Law may not be the best formatted site on the web, but the content is great. I also HIGHLY recommend his book Legal Language, which is a great piece for academics and professional lawyers alike.
For those who are interested in a more linguistic-focused analysis of how legal language came to be, and why it persists, John Gibbon’s book Forensic Linguistics is good. Personally, I found his text not as accessible as Tiersma’s from the perspective of a professional lawyer wishing to improve my language when I had both texts as prescribed reading for this postgraduate law unit at Monash. (Which was a bit awkward, considering that John was one of the lecturers…) But his work and research is really useful at unravelling the why in the question of “why do lawyers use such confusing language?” He is also one of the few linguists whose work has been recognised by the legal system, and he has been involved in improving the language used by interviewing police, and has been called as an expert witness in cases in Australia and the UK (details in his textbook.)
Similarly, Diana Eades work on sociolinguistics is great. Sociolinguistics and the Legal Process is really good, and has a lot of really useful examples about the lack of clear communication by lawyers and legal systems drawn from her research with Aboriginal and Torres Strait Islander peoples in the criminal justice system. This book definitely should be prescribed reading for anyone working at an Aboriginal Legal Service in my view!
Another essential item for lawyers working in Australia with Indigenous peoples is the excellent Northern Territory Law Society Indigenous Protocols.
One of the early works on legal language was David Mellinkoff The Language of the Law. While it was published in the 1960s and draws most of his examples from American legal history and practice, I found it to be a really good read and he draws the links between the historical development of lawyers as a professional class, and the insistence on using legal language to distinguish that class.