Interpreting can be done in different ways, depending on the setting, how much time is available, how many languages are used, and whether or not technology is available.
Conference interpretation can be simultaneous or consecutive.
The interpreter sits in a booth, listens to the speaker in one language through headphones, and immediately speaks their interpretation into a microphone in another language.
The interpreting equipment transmits the inteepretation to the headphones of the listeners in the meeting room.
Simultaneous interpretation is appropriate in bilingual or multilingual meetings and has the advantage of not lengthening the meeting. It encourages a lively discussion and more spontaneous contributions.
Simultaneous interpretations requires a high level of concentration, since the interpreter is doing several things at once:
listening and speaking.
analyzing the structure of what is being said in order to present the spearker's argument.
listening to his/her own interpretation to check for slips of the tongue.
Interpreters therefore take turns of about 30 minutes.
The interpreter is in the same room as the speaker and follows their speech while taking notes before presenting the interpretation.
Very long speeches may be broken up into parts, with interpretation after each part, but a trained interpreter is capable of consecutive interpretation of speeches several minutes long.
This kind of interpretation is suitable for scientific and technical presentations given by a single speaker, or in meeting where only a small number of languages are spoken, since it makes the meeting longer.
Note taking is an essential part of consecutive interpreting. It involves committing to paper the logic and structure of the statement as an aid to memory, rather than recording everything that is said.
AIIC. "How interpreters work". aiic.net. November 28, 2011. Accessed April 20, 2017. <http://aiic.net/p/4005>.