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; sitting in a sound-proof booth, the SI interpreter speaks into a microphone, while clearly seeing and hearing the source-language speaker via earphones. The simultaneous interpretation is rendered to the target-language listeners via their earphones. The equipment used are referred to as simultaneous interpretation equipment. NOTE: Laymen often incorrectly describe SI and the SI interpreter as ‘simultaneous translation’ and as the ‘simultaneous translator’, ignoring the definite distinction between interpretation and translation.

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 the speaker progresses through the message. When the speaker pauses or finishes speaking, the interpreter then renders the entire message in the target language. Consecutive interpretation is rendered as “short CI” or “long CI”.

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. Chuchotage is used in circumstances where the majority of a group speaks the source language, and a minority (ideally no more than three persons) do not speak it. (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 the speaker progresses through the message. When the speaker pauses or finishes speaking, the interpreter then renders the entire message in the target language. Consecutive interpretation is rendered as “short CI” or “long CI”.

Liaison interpreting involves relaying what is spoken to one, between two, or among many people. This can be done after a short speech, or consecutively, sentence-by-sentence, or as chuchotage (whispering); aside from note taken then, no equipment is used.

Relay interpreting occurs when several languages are the target-language. A source-language interpreter renders the message to a language common to every interpreter, who then renders the message to his or her specific target-language. For example, a Japanese source message first is rendered to English to a group of interpreters, then it is rendered to Arabic, French, and Russian, the other target-languages.