About the degree of knowledge of a C-language

I just would like to express my opinion about the degree of knowledge of a C-language to accomplish the task of C.I. Many have argued it’s need to have a full/perfect passive knowledge of the C-language: full stop. But let’s try to redefine the definition of “full knowledge”: if we assume that a fully comprehensive understanding (including diamesic, diastratic, diachronic, diatopic and diaphasic variations) = bilingual, assuming that nobody is a sort of “supreme being” - which is to say that what I try to express is conceived within a normal human skills repertoire, it’s clear how the fact of possessing a complete reference mold (including culture-bound issues embracing long time spans, idioms etc.) for five or more languages seems to be pretty impossible: we should have had many lives at once or claim the theory of parallel universes. By the way, I think it actually is utterly possible to accomplish C.I. tasks from 6… 7… 8… passive languages, but then it’s matter of state-of-the-art strategies (as well as the knowledge of the “conferencish” pidgin) enabling the interpreter to insure a decent, smooth delivery even in case of lack of understanding of a particular speech segment, maybe because it’s related to a deep culture-bound issue (for example: an idiom related to a 70’s spanish washing-up soap advertisement or the sudden recall to a local character unknown to the interpreter) or a particular structure/ variety/ expression never heard before (I also would like to put the stress on the fact that success is also related to the conditions in which the interpreter is supposed to work, but this is a different kettle of fish I don’t want to handle in this short post). This contribution is intended to have a cheering-up spirit, I just would like to say that focusing on C.I. techniques is quite as important as the language master, in order to achieve this satisfactory sensation of “closure of the circle” in any C.I. delivery from any C-language.
Have a nice weekend!