This type of interpretation is used in conferences, tribunals and courts. It is instantaneous interpretation from one language to other. Ideally while the interpreter is performing simultaneous interpretation, he or she sits in back stage or in a booth with at least one or two colleagues using special equipment, which enables them to perform the task (headphone and microphone).
The interpreter wouldn’t be able to interpret until he understands the full meaning of sentences, and has located the subject and verb. Performing simultaneous interpretation can be a hard task, as the interpreter has has to simultaneously interpret into the aimed language while recalling, understanding and paraphrasing the next sentence. The key to simultaneous interpreting is avoiding any delay, which will make the task more difficult. There is no time to weigh or recall the right terminology in the language.