Since multiple languages are handled in with the indices:
- Stemming/Lemmatization and stopwords need to be handled language-wise
- User can select what documents to search
[This guide](https://www.elastic.co/de/blog/multilingual-search-using-language-identification-in-elasticsearch) lays out strategies to handle multiple languages with language identification:
1. Identifying the language of a specific field at index time
2. Identifying the language of a document and select the language-specific index for the doc
