Change documents language
Change language to a set of documents
To change language to a set of documents in the Documents tab, list view:
Ctrl-clickto select the documents.- Select Change language 
 and select the language from the menu. 
Change language to a single document
To change language to a single document in the Documents tab, list view:
- Select the language icon beside the text (Change language), then select the language from the menu.
 

Or:
- Select the document, select Change language 
 and choose the language from the menu.