Expressing "There is" (Existential Clauses)
To say that someone or something exists in a particular place (like "There is a man in the sauna" or "There is a bird on the roof"), Finnish uses a specific sentence structure called an existential clause.
Instead of using a dummy word like the English "there", Finnish simply starts the sentence with the location. The formula is:
Location + on + Subject
The location will be in a location case, such as the inessive (-ssa / -ssä for "in"). The verb is the 3rd person singular on (is), followed by the thing that exists there (the subject).
Using the Adessive Case for "On"
The same structure applies when the location is an open space or a surface. In this case, you simply start the sentence with the adessive case (-lla / -llä for "on" or "at").
Asking Questions: "Is there...?"
To ask if something is in a location, we move the verb to the beginning of the sentence and attach the question particle -ko / -kö.
Because the verb in these sentences is always on, the question will start with Onko (Is there...?). The location comes immediately after the verb:
Onko + Location + Subject?
Multiple Subjects in Existential Clauses
If you are listing multiple things that exist in a location using ja (and), the verb remains the singular on. In existential clauses, you do not need to change the verb to the plural form even if there are several subjects.