This module differs from this one: http://drupal.org/project/search_api_et. It uses an alternative way of getting language aware search with entity translation: have one index per language. This has some drawbacks like scalability and site building usability. But when used with Solr as indexing backend, it allows to set a different configuration for each language (by declaring one Search API server per language, matching to a different Solr core). This especially makes sense if the website only has two or three languages. For more info on these considerations, see http://drupal.org/node/1393058.