I use a search for the blog articles. The blog articles are organized in a collection for German and a collection for English.
The blog overview is available for both languages:
on both sides the search is integrated. However, from both sides you get to the same search results page with the German headline. My wish would be that if someone comes from /en/blog an english headline is displayed.
Ideally, only the results from the English collection should be shown and if someone from /blog comes the German headline and the results from the German collection.
its not possible to have more than one search index. (source)
So that being said its not possible to show only one language without custom code (which will scan through all result links and check if there is “de” or “en” within the url).
You may can solve this by using the [[de]] tags for displaying different languages in certain fields. And maybe its possible to just add these tags in the Site-Search Description/Name fields of your Blog Collection Page.
Take a look here for the tutorial how to do it:
But i think the custom code should be pretty easy to write and implement.