Interpreters' working languages are classified in three categories - A, B, C:
• The 'A' language is the interpreter's mother tongue (or its strict equivalent) into which they work from all their other working languages in both consecutive and simultaneous interpretation. It is the language they speak best, and in which they can easily express even complicated ideas. It is therefore an active language for the interpreter.
• A 'B' language is a language in which the interpreter is perfectly fluent, but is not a mother tongue. An interpreter can work into this language from one or several of their other working languages, but may prefer to do so in only one mode of interpretation, either consecutive or simultaneous (often in 'consecutive' because it's not so fast). It is also considered an active language for the interpreter.
• A 'C' language is one which the interpreter understands perfectly but into which they do not work. They will interpret from this (these) language(s) into their active languages. It is therefore a passive language for the interpreter.
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