Ordinals 11 to 20 in the essive case (-ntena / -ntenä)

Ordinals 11 to 19 in the Essive Case

To express when an event happens on dates from the 11th to the 19th, use the essive case (-na / -nä) on the ordinal number. For these numbers, which end in -toista, only the first part of the number inflects, while -toista remains unchanged.

Plural Events and the Higher Teens

Some event nouns, like messut (a fair) and häät (a wedding), are always plural and take plural verbs (like ovat instead of on).

The ordinal essive rule remains the same for the higher teens:

The 20th: Kahdentenakymmenentenä

For 20 (kaksikymmentä), both halves of the word inflect fully in the ordinal essive.

"On the second" is kahdentena, and "on the tenth" is kymmenentenä. Combined, "on the twentieth" is kahdentenakymmenentenä.