päätettäessään

Päätettäessään is a Finnish grammatical form, specifically the inessive case of the third infinitive of the verb "päättää" (to decide). The third infinitive in Finnish is a verbal noun that can be used in various case endings to express different grammatical functions. The inessive case, indicated by the ending "-ssään", signifies that the action is happening within or during the time of the event expressed by the infinitive.

Therefore, "päätettäessään" translates roughly to "while deciding" or "upon deciding" or "in the process of deciding." It describes a situation where the subject of the main clause is performing the action of deciding simultaneously with another action. For example, "Hän löysi avaimet päätettäessään lähteä" means "He found the keys while deciding to leave."

This construction is common in Finnish to express temporal relationships and the context in which an action occurs. It emphasizes the ongoing nature of the decision-making process at the moment another event takes place. Understanding the function of the third infinitive in different cases, like the inessive, is crucial for grasping the nuances of Finnish sentence structure and expressing complex ideas clearly.