Kielessäkin
Kielessäkin is a Finnish phrase formed from the noun kieli (tongue, language) in the inessive case kielessä meaning “in the tongue” or “in language,” together with the particle -kin meaning “also” or “even.” The result is an adverbial expression that can be translated as “even in the tongue” or “even when spoken,” used to emphasize that a statement or phenomenon applies to language or speech as well as to other aspects.
Kielessäkin is used in both spoken and written Finnish to add emphasis or to introduce a contrast
A typical usage would be something like: “Kielessäkin se kuullostaa oudolta,” meaning that the thing sounds
Kielessäkin is a productive and idiomatic construction in Finnish. It illustrates how the language uses case