Essive and Translative: -na, -ksi

The essive (-na/-nä) describes a role or a temporary state: as something, or when one was something.

• Hän on töissä opettajana (She works as a teacher).
• Lapsena olin ujo (As a child I was shy).
• Kahvi on parasta kuumana (Coffee is best hot).

The translative (-ksi) describes a change: what someone or something becomes. Typical verbs are tulla (become), muuttua (turn into), valita (elect) and opiskella (study to be).

• Sää muuttuu kylmäksi (The weather is turning cold).
• Haluan tulla lääkäriksi (I want to become a doctor).
• It also means 'in a language': suomeksi (in Finnish).

The translative takes the weak grade like the genitive (äiti → äidiksi); the essive keeps the strong grade (äitinä).