There are as many aspects of legal translation as there are specialties. Since one translator cannot possibly cover all of them, turning to a bureau is a good bet for finding a variety of qualified translators and editors.
Our relationship with a law firm starts with helping lawyers and paralegals to sort through foreign documents and establish relevance to the case at hand, enabling them to reduce the cost of translation by focusing only on documents that actually need translating. Often it is enough just to give the researcher an idea of what the document is about; other times a written abstract is required. Sometimes it is necessary to do research in a foreign country. In those cases our work is better described as project management rather than "just" translation.
Patent translation is a very specific field in which we have decades of experience. We know how important accuracy is in a world where years of research culminating in intellectual property are at stake. It is a rare breed of translators who combine linguistic skills, including the special language of patents ("patentees"), with technical know-how. We have two such individuals on staff who started their careers as engineers and brought along their technical expertise to their translating career. Again, familiarity with the issuing country helps. For example, when translating a Hungarian patent, there was a term that was not part of the PCT vocabulary. We found that at the time of this particular patent, the Hungarian Patent Office had, in addition to novelty, inventive merit, and industrial applicability, a fourth item, "progressive nature," a term unknown even to patent attorneys in the U.K or US. We were able to clarify the definition of this item as "an approach that represents progress compared to the state of the art, meeting a need unsatisfied until then, or providing a more advantageous approach to satisfying that need."
In order to translate legal documents, the translator needs to be familiar with both the source and target countries' legal system. A Swedish divorce decree, for example, will contain insight into their legal aid system. When it comes to translating German legal documents, it is not enough to rely on your knowledge of the German legal system that was current in the 1980s. Profound changes following the collapse of the Third Reich and, again, the creation of the European Union are reflected in the legal documents of each period.
A good legal translator also needs to know how to translate a document referring to legislation that does not exist in the target country. Consumer protection laws, e.g., may have a variety of versions and implications in different countries. Contract law is another area where faulty translation may have dire consequences. No sooner did the former Russian satellite countries get used to the free-market economy, now they have to realize that a great number of regulations and laws are coming from Brussels or Strassbourg rather than Budapest or Prague. But there are a lot of questions; German contract law raises a lot of questions in regard to the laws of the EU. As Europe is struggling to form a common frame of reference for union members, business doesn't stop. It is up to the translator to bridge the differences.
Labor law is another area that requires careful attention, especially when an international company opens a manufacturing site. We had the privilege of helping a German. automaker understand Mexican labor law, including the RFSHMAT (Reglamento Federal de Seguridad, Higiene y Medio Ambiente de Trabajo - Regulation for Safety, Health, and Environment in the Workplace) and the NOMs (Normas Oficiales Mexicanas - Official Mexican Standards). Only that way could they apply the OSHA regulations, making sure that both countries' laws were observed. It was not enough to know the languages of the two countries; understanding the two systems and knowing the target audience were equally essential.