The interpretation resources included below are not necessarily endorsed by the U.S. Department of Justice or by the Federal Interagency Working Group on LEP.
"[T]he ordinary or common meaning of 'interpreter'...is normally understood as one who translates orally from one language to another." Taniguchi v Kan Pac. Saipan, Ltd, 132 S Ct 1997, 2003-04 (May 21, 2012).
Administrative Office of the U.S. Courts, Federal Court Interpreters
National Center for State Courts, State Interpreter Certification
National Board of Certification for Medical Interpreters, Credential Program
The Certification Commission for Healthcare Interpreters, Certification Program
The American Translators Association, Interpretation Getting it Right: A guide to buying interpretation - 2011
Immigration Court Interpreters, Their Standing as Professionals (PDF), National Center for State Courts - May, 2000