The English-speaking lawyer uses Latin terms frequently.

For example:

Ultra vires (beyond powers) is applied especially to acts of directors exceeding the scope of powers granted by the articles of association of the company or the laws of the state of incorporation. e.g. "The School Board engaged in a variety of ultra vires activities." Compare intra vires (within limited powers).

Translegal Digest (http://www.translegal.com/digest/modules/smartnews/item.php?itemid=2)

Stare decisis: Ater-se a/ou respeitar caso(s) já anteriormente decidido(s). Coisa julgada. Efeitos vinculantes. "to stand by things decided/by a decision". Used in common law to express the notion that prior court decisions must be recognized as precedents, according to case law. The doctrine under which a trial court is bound by appellate court decisions on questions of law which are raised in the lower court. Trail courts cannot ignore precedents and must rely upon them until an appellate court changes the rule. Adherence to this doctrine insures certainty, consistency, and stability in the administration of justice. “He argued that the court was compelled by the principles of stare decisis and controlling precedent to dismiss the case.”