Breakdown of Kurssi alkoi kolmantenatoista helmikuuta.
alkaa
to start
helmikuu
February
kurssi
course
kolmastoista
thirteenth
Questions & Answers about Kurssi alkoi kolmantenatoista helmikuuta.
How do you build kolmantenatoista (on the 13th) from the basic number 13?
The basic number 13 is kolmetoista, and the ordinal "13th" is kolmastoista. To say that something happens on a certain day, we use the essive case ending -na. For numbers ending in -toista (the "teens"), only the first part changes. The stem for kolmas (third) is kolmante-, so adding -na makes it kolmantena. Then, just attach the unchanged -toista to the end!
Why is the month helmikuuta in the partitive case?
When expressing dates in Finnish, the month is always in the partitive case. This is exactly like saying "the thirteenth of February" in English. The basic word helmikuu gets the partitive ending -ta because it ends in two vowels.
I remember that alkaa (to start) has consonant gradation (like minä alan). Why is the "k" still there in alkoi?
Good catch! The verb alkaa does undergo consonant gradation, where lk weakens to l in closed syllables (like al-kam-me, which becomes alamme). However, the third-person singular past tense ending here is just a vowel (-i), which leaves the final syllable open (al-koi). Because the syllable is open, the strong grade lk is kept.