The speaker may speak for a few minutes or upwards of a half hour. Also, consecutive interpreters are usually expected to interpret into and out of their native language. Simultaneous interpretation by contrast is typically done in a booth. The interpreter listens to the speaker using a set of headphones, then instantly renders the speech into the target language, almost always the interpreter's native language. In simultaneous interpretation, the interpreter is rarely more than a few seconds to a minute behind the speaker, and though the quality and accuracy of the interpretation are not nearly as high as they are in consecutive interpretation, the speed and intensity are much higher.
Interpreters are different from translators.
They need to be extremely fast with their languages, capable of making snap decisions even when not at all certain about what a speaker is saying. They must be poised and composed, even when working with angry officials or attorneys, business tycoons, or heads of state, have excellent spoken languages skills, including the ability to listen very accurately under less than ideal ambient noise conditions, and good oral presentation and public speaking skills in all of their languages. Travel is a frequent part of interpretation work, with some assignments, such as escort work with the U.S. State Department, lasting upward of three weeks. I strongly recommend that anyone interested in interpretation take the time to talk to working interpreters and look carefully at getting some professional training. Both consecutive and simultaneous interpretation require the development of a very precise set of skills, neither of which could easily be obtained on the job.