käydessään

Käydessään is a Finnish grammatical form. It is the third infinitive form of the verb, specifically the adessive case of the verb stem. This form is used to express an action that is happening concurrently with or immediately after another action. It functions similarly to the English "-ing" form used in certain contexts, such as "while doing" or "upon doing."

The structure of käydessään involves the verb stem followed by the suffix -essään. For example, with the verb "tulla" (to come), the form is "tullessaan," meaning "while he/she/it was coming" or "upon his/her/its coming." The possessive suffix -än in this context refers to the subject of the main clause, indicating whose action is being described.

This form is particularly useful for creating more fluid and descriptive sentences in Finnish, avoiding the need for separate clauses connected by conjunctions like "kun" (when) or "samalla kun" (at the same time as). It can convey a sense of immediate succession or simultaneous occurrence. For instance, "Hän lauloi kävellessään" translates to "He/She sang while walking." The usage of käydessään adds a stylistic nuance and conciseness to Finnish expression.