If the word ends in a, ä, o, ö, u or y, there are no changes in the stem before the ending.

vauva: vauvan nimi

isä: isän nimi

vaimo: vaimon nimi

 

Word type e → ee

If the last letter of the base form of a word is e, it belongs to the word type -e. Another e is added to the word stem. In singular partitive, add -tta/-ttä.

oire: Milloin oireet alkoivat?

vene: Soudamme veneellä.

huone: Meillä on neljä huonetta ja keittiö.

 

Word type i → i

Words that end in -i are divided into several different groups depending on the changes that occur at the end of the word. Newer words ending in -i have no changes at all. This group includes many loanwords from other languages, like kurssi, hotelli, bussi. 

 

Word type i → e

Words ending in -i can be distinguished from each other by their meaning. Usually, words referring to nature, animals, or body parts are old words ending in -i. In old words ending in -i, the i changes to e when the ending is added.

suomi, kieli: Suomen kielen kurssi alkaa yhdeksältä.

 

Some words may look old words, but really they are loanwords, too, and came to Finnish relatively early. These include e.g. äiti, kahvi, hissi, where the i does not become an e. 

kahvi: Minä en pidä kahvista.

äiti: Mikä sinun äidin nimi on?

 

Old words ending in -i have different endings in partitive. If the word ends in -ki, -pi, -ti, -mi, -vi, its ending in singular partitive is -a/-ä. If the word ends in -hi, -li, -ri, its ending in singular partitive is -ta/-tä.

suomi: Minä opiskelen suomea.

järvi, joki: Kuinka monta jokea ja järveä Suomessa on?

lohi: Joessa on lohta.

kieli: Mitä kieltä sinä puhut?

meri: Katselen merta.

 

Word type si → de (te)

If an old word ends in -si, its ending in singular partitive is -tta/-ttä and in other cases its stem ends in –de. For example, the word uusi is part of this group.

Minä etsin uutta asuntoa.

Uudessa hississä on iso peili.

Muutin eilen uuteen kotiin.