As recently as the 1940's Latin was a requirement of the law degree in New Zealand. Latin and Greek were essentials of an arts education in most European countries, and the settlers ensured that all the schools taught these. Both lawyers and doctors were expected to have at least a grasp of the basics. Our present Chief Justice has made no secret of her desire to remove as much Latin as possible from New Zealand law. The problem is the perception of Latin as an elitist subject used to ensure that law is kept as an arcane secret from the common herd. But, Latin has been an integral part of the common law from its beginning. The use of pithy Latin phrases often carries significant meaning, much as maori proverbs do. The limit has been reached however in the new District Court Rules where I find that the plural of "memorandum" has become "memorandums". Alas, the barbarians have entered the city and reside in the Parliamentary drafting Office. To this I can only say o tempora o mores!
The English House of Lords does not have such inhibitions. I noticed in the recent case of Moore Stephens (a firm) v Stone Rolls Ltd  UKHL 39 (30 July 2009) the first judgment began by citing the legal maxim of "ex turpi causa non oritur actio" without providing a translation. Clearly English lawyers are expected to understand. We risk being seen as uneducated and rustic colonials in the Common Law world.
(Any non lawyer readers who need translation should ask)