Translation work usually involves many translation directions. A translation direction is a pair of languages, of which one is the source language and the other the target language of the translation work. The source language is the language of the the original text from which the text is translated. The target language is the language into which the text is translated. The direction of the translation is not negligible, since the ability to translate in one direction does not necessarily imply the ability to translate in the opposite direction. Very often the target language is the native language of the person doing the translation work.
Typically some translation directions are more important than others. Effectively this dimension can be described by the set of translation directions and the respective quantities of text translated in each such pair. This dimension determines what language skills are needed in translation work. It may also help determine how the translation activity should be arranged by the organization.
Normally the translation directions are not random. Often there is at least one language which is a major source language or target language or both at the same time (though the European Community is an example of a truly multilingual organisation without, at present, focal source languages). Such a language will be called a focal language in this text. Usually the focal language is the national language, but there may be one or two others. It is even possible that the national language is not a focal language at all. Typically focal languages are used as intermediary languages when a translation is needed to or from a rare language. In such a case, English is the focal language par excellence.
Typically organizations have up to ten or slightly more translation directions, 2-4 language pairs, and 1-2 focal languages. If translations concern more languages, the translation is usually done via an intermediary language in which the organization has the necessary language skills. An exception is the European Community's SdT, with a much larger number of language pairs dealt with directly. See the annex on this institution).