Feed import save empty value in multilingual site
Feeds: Entity Translation


  This module adds support for importing data through Feeds into
  translatable fields handled by Entity Translation.
  
  The module exposes fields that are translatable into all enabled
  languages, enabling the creation of translations of entities when
  importing.


Another fantastic Solution 

Import from two xml files (on for each language), my empiric solution :


I created two feed imports.
I forced the language field for each one.
Two separated nodes were created for each content (one in each
language) but it didn't links the translations.
So I used a SQL query to finish the job, it's based on the feeds uuid