Localizing from an alternate language (pivot language localization)
A pivot language is used as intermediate language when a direct translation between the source language and the target language is not available.
This may occur when your translation vendor does not offer a direct translation from your source language or it is too costly to perform a direct translation. For example, you want to localize into Arabic from Japanese, but your translation vendor does not offer Japanese to Arabic (or it is too expensive); however, they do offer Japanese to English and English to Arabic. This means that you need to use English as a pivot language so you can create a sequence to localize Japanese into English and then English into Arabic.
When pivot language localization is enabled, the DITA CMS administrator configures which languages can be localized into which languages. Although an object can be localized in any available language as defined in the configuration files, once an object has been localized from a pivot language, you cannot shortcut its localization sequence. For example, if you have localized a map and its child objects from Japanese to English to Arabic, you cannot go through the cycle of updating that map and its child objects from Japanese directly to Arabic.
When a source object is translated for the first time into a language, DITA CMS creates a new object in the target language (referred to as a language object). This language object has its own Revision number as well as an Authoring Revision property, which stores the revision number of the source object when it was sent for translation. With pivot language localization, the source object is not necessarily in the Authoring cycle. For example, if you have localized from Japanese to English to Arabic to Indonesian, the revision number stored as the Authoring Revision for the Indonesian language object comes from its source object (the Arabic language object), not the originally authored content (the Japanese object).