What of these is the most common used letter in Finnish V K or Y?

The most common letter in Finnish is K.

Here's a breakdown:

* K is the most common consonant, appearing frequently in words like "kaksi" (two), "katu" (street), and "kirkko" (church).

* V is fairly common but less so than K.

* Y is also relatively common, but typically less so than K and V.

Let me know if you'd like to explore the frequency of other Finnish letters!