Another language is set as default for the portal, but still en_US suffix gets attached to the search index of a document. I examined the results in a Chrome extension called ElasticSearch Head.
- Instance settings > Localization > Set Slovak as default language
- Content & Data > Add new Document Type
- Main Metadata Fields > Add a Text field and save it
- Documents and Media tab > Add new document with the newly created doctype and publish it
- ElasticSearch Head > ddm_keyword34926_Text7t48_en_US
In case of a Web Content, it is indexed properly with sk_SK suffix