Is Search API module 'English-speaking' only? I am developing a multilingual (English-Ukrainian) Drupal website using Entity translation module. Everything went smooth before I tried to use the search module. I have Search API, Database search, Search API Entity Translation and Search API Entity Translation Database Search enabled and configured.

As far as I understand, only the English version of content is being indexed. All search queries in Ukrainian have zero results.

As an experiment I added some English words to the page in Ukrainian and used them as search terms. To my surprise, the page containing these words immediately appeared in search results. Furthermore, when performing the same seach from the English version, the English version of the Ukrainian-language page containing these keywords was retrieved (there are no such keywords in English version).

Is it possible for Drupal search to index content in Ukrainian (or other cyrillic language)? Are there any guidelines or tutorials how to acheieve this in multilingual environment organized with Entity translation?

UPDATE:

Continue experiments.  I have three nodes, all of them translated. After disabling "Search API Entity Translation Database Search" module the situation changed. Two of nodes have their Ukrainian versions indexed only, the third one has only English version indexed. I have re-indexed the website several times. All three nodes and their translations are similar.
You;d need to use the Search API Entity Translation module to have this work as expected.

Going further if you wanted more control of the system and were using Database based indexes you would also want to install Search API Entity Translation Database Search