Often times interpretation and translation are used interchangeably. I see examples of this error everywhere in popular media. The popular movie The Interpreter helped educate the public about the field. I am glad to see the US Government recently released a video to define the types of interpretation found in the US Court system.
Translation is taking text in one language and translating the material into another language. I like defining interpretation as the act of bridging a language gap between two individuals through speech.
This video posted on the uscourts.gov site explains the different types of interpretation and how it is used in the court system. The types of interpretation explained in the video are simultaneous and consecutive.