1) Conference interpreting was developed during World War I to facilitate international meetings where not all attendees spoke the same language. Simultaneous interpreting later became widespread at international conferences, radio/TV programs, lectures, and state visits.
2) Conference interpreters typically have 2-3 working languages: an A language which is their native language, a B language of good proficiency but not native, and optionally a C language of more passive understanding.
3) The history of research on conference interpreting can be broken into four periods from the 1950s to present: early writings by pioneers, experimental psychological studies in the 1960s-70s, practitioner-focused period, and a renewal period incorporating different perspectives.