The interpreters are stationed in a booth, use headphones to listen to the speakers, and translate what they say into the microphone with a 2 or 3-second delay. The audience (listeners) wear receivers on their ears to listen to the interpreters. Simultaneous interpreting requires an extraordinary amount of concentration because the interpreter must listen to what the speaker is saying at the same time as they are translating what has already been said.
Depending on the length and nature of the meeting, simultaneous interpreting teams usually consist of 2-4 interpreters working in a 15-20 minute rotation.
Simultaneous interpreting tends to be used mostly at major international conferences, large meetings and long meetings.