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. Moreover, SI is the common mode used by sign language interpreters. 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. Source.
Tags: What is Simultaneous Interpreting? Simultaneous Interpreting, Language Interpreters, Interpretation versus Translation, Interpreting.