The definition of simultaneous interpretation implies the immediate translation of what is said from one language into another as the speaker is making a presentation.
This type of translation is normally used in international meetings and congresses to allow people of different languages to follow the proceedings in their own native tongue.
The simultaneous translation is usually performed by 2 interpreters seated in a sound-proof booth;
They listen to the speech through earphones and translate simultaneously speaking into the microphones fitted inside the booth.
The translation can be heard through earphones distributed at the beginning of the event.
In cases where there are several languages spoken by participants ( and therefore a requirement for more booths), the listener can choose the desired channel through a channel selector provided to each participant along with the earphones.
Simultaneous translation is a form of interpretation that requires concentration and rhythm.
Translating along with the speaker means listening in one language and speaking in an other, and at the same time processing the information.
There is a small gap between the speaker’s words and the interpreter’s ones called “décalage”.
It is of crucial importance that the interpreters in the booth alternate every 20-30 minutes in order not to lose focus.
Interpreter can not work alone in the booth for more than 40 minutes without jeopardizing the quality of their work.
The interpreter, even though depending on the rhythm of the speaker, must produce a flowing translation avoiding sudden stops and change of speed and also avoiding a flat and mechanical tone which would be tedious to the listeners.
The difficulties in simultaneous interpretation include plays on words, idiomatic sentences and sayings which are often untranslatable;
The use of slang also presents problems.
Speakers should try to provide interpreters with abstracts and texts relevant to their presentations beforehand, specifying the meaning of acronyms to be used and preparing a short glossary if the language used is very technical.

