Pivot Language is a basic notion of translation management, which all programmers and administrators of a multilingual CMS should be aware of, although it doesn't necessarily entail the development of a specific feature.
Pivot Language notion comes the difficulty that organisations meet when dealing with a large number of translations, in languages that are not quantitatively equal as to their userbase: there comes a limit where you don't find enough translators for one of your languages.
Please note we are not talking here of the unequality of languages in terms of quantity of native speakers, but about the unequality of languages in terms of people who can read them as a second language, and translate them into their native language. For instance, In France many people can read English, few people can read Chinese. This is not about the number of people who can read English or Chinese in the world, it is about the possible number of translators into French.
When you run a site with more than two languages, ideally you recruit translators for all possible languages combinations. The number of those combinations is not exactly the number of language pairs, but the number of Source language -> Target language combinations, that is the number of language pairs x 2. For instance, in France again, although many people will be able to translate from English into French, you should not assume that the same people will be able to translate from French to English.
The concept of Pivot language emerged first in the European community institutions, who deal with a quite large numbers of publications, and it is important to note here that they are legally compelled to translate official texts into all official languages.
The ambition was at first to recruit translators for any Source language -> Target language combination. However although they found too many candidates for English to French and French to English, they could not find enough people for Danish to Maltese, Finnish to Portuguese... in order to translate all documents systematically.
Therefore it was decided that any document meant to be translated in all languages of the European Union should translated in English or French first, and then translated into all languages. Thus translation managers only have to recruit translators from English or French towards native language.
The application of the concept of Pivot language to such a CMS as Tikiwiki could lead to an ordering of tne succession of translation into specific languages, inside a global process of translation. to put it more simply, Admin will chose a Pivot language, and the process will be:
1) A text in a rare language is submitted
2) Translator from that rare language into Pivot Language are requested to translate
3) All translators from Pivot language are requested to translate into their own rare language
This kind of process is frequently applied by Japanese translation agencies, who know they will find few people abroad who read Japanese, and many who read English. It also offers the advantage that editors will fully control the one and only source text in Pivot language, instead of letting versions of versions of versions proliferate, that you cannot check yourself.
It is likely this feature would be appreciated by companies with a dedicated budget for translators and translation managers. Many non-profits with volunteer translators however would chose not to use it, since they will be eager to accept any translation opportunity, even from a rare language into a rare language.