The translative generally expresses a state, property, function or position into which something or someone enters, or the end point of a movement or change.
So why is translative correct in the following sentences?:
1. Tämä riittää perustelu/ksi. (This suffices as an explanation.)
I would have used Essive (perustelu/na)
2. Auli luuli minua norjalaise/ksi. (Auli thought me a Norwegian.)
I would have used Essive (norjalaise/na)
3. Turkua sanotaan vanha/ksi kaupungi/ksi. (Turku is said to be an old city.)
I would have used either nominative or essive (vanha/na, kaupinki/na; vanha, kaupunki)
4. Vennamoa ei saa kutsua idiooti/ksi. (Vennamo must not be called an idiot.)
I would have used either Essive (idiooti/na) or Nominative (Idiooti)
5. Nouse ylemmä/ksi! (Get up higher!)
Just nominative: Ylempä
Paljon kiitoksia!