In consecutive interpreting (CI), the interpreter speaks after the source-language speaker has finished speaking. The speech is divided into segments, and the interpreter sits or stands beside the source-language speaker, listening and taking notes as the speaker progresses through the message. When the speaker pauses or finishes speaking, the interpreter then renders a portion of the message or the entire message in the target language.
In simultaneous interpretation (SI), the interpreter renders the message in the target-language as quickly as he or she can formulate it from the source language, while the source-language speaker continuously speaks; a spoken language SI interpreter, sitting in a sound-proof booth, speaks into a microphone, while clearly seeing and hearing the source-language speaker via earphones.
In whispered interpreting (chuchotage, in French), the interpreter sits or stands next to the small target-language audience whilst whispering a simultaneous interpretation of the matter to hand; this method requires no equipment, but may be done via a microphone and headphones if the participants prefer. Chuchotage is used in circumstances where the majority of a group speaks the source language, and a minority (ideally no more than three people) do not speak it.