TL;DR: Special:Search should have language links to Special:Search in other languages.
[this is based on a user story of a new user I heard]
- Someone see in the language links in a "source wiki" (hewiki) a link to another language ("target language"; ruwiki) and press it.
- After reading the article (ruwiki) she uses Special:Search in the ruwiki and search in Hebrew
- 0 results in Special:Search in ruwiki for a Hebrew word (which is fine) but: there are no even language links from Special:Search.