[xwiki-users] : XWiki context

Hi All, I would like whether someone help me on how to set the language or change the default document language with "Groovy". In some situations, when creating some of documents I don't need to specify language even language of content is different of that indicated on the top. Now for some documents, I need to create documents for which default language is different from that of XWiki. In fact, I tried to invoke 'XWikiContext.setLanguage("language")' but it seems that "saveDocument()" method don't work with "XWikiContext". I would like also to understand difference between "XWikiContext", "context.context" and "xwiki.api.Context"? If before saving any document we need to specify the "context" then how to modify this context. There are less methods are available for tuning this contex (I mean "context.context"). Many thanks in advance. Youcef