rationalskepticism.org

Finnish has no regular verbs. Verbs are of six types. To be is very much like the others in its group.
https://en.wikipedia.org/wiki/Finnish_verb_conjugation
minä olen
sinä olet
hän on
me olemme
te olette
he ovat

The hint of irregularity is in the they are with the v. But it is the same as the verb pesee, to wash
minä pesen..I wash
hän pesee ..he washes
he pesevät..they wash