Appendix:Finnish polarity pairs

In Finnish, the clitics -kin and -kaan / -kään, and some words (mainly adverbs or conjunctions) in which they have become lexicalized, form polarity pairs, where the former is used as a positive polarity item and the latter as a negative polarity item.

This means that in affirmative and negative sentences, the positive (-kin) and negative (-kaan) polarity forms are generally used, respectively:

Kesä ehkä sittenkin meni jo. (positive)
Perhaps summer is already gone, after all.
Ei tämä sittenkään toimi. (negative)
This won't work after all.

However, in interrogative sentences (questions), either can be used, but the nuance is different:

Oliko tämä sittenkin hyvä idea? (positive)
Was this a good idea after all?
"It might have seemed like a bad idea, but now I think it might have been a good idea."
Oliko tämä sittenkään hyvä idea? (negative)
Was this a good idea after all?
"It might have seemed like a good idea, but now I think it might have been a bad idea."

Note that the polarity also applies to certain grammatical features, such as the marking of telic objects in sentences:

Onko hän kuitenkin syönyt kakun? (positive)
Did he eat the cake anyway?
"We thought he hadn't eaten the cake, but has he after all?"
Onko hän kuitenkaan syönyt kakkua? (negative)
Did he eat the cake anyway?
"We thought he had eaten the cake, but has he after all?"

The polarity of these words does not have to correlate with the presence or absence of ei in the sentence:

Eikö tämä sittenkin ollut hyvä idea? (positive)
Wasn't this a good idea after all?
"It might have seemed like a bad idea, but now I think it might have been a good idea."
Eikö tämä sittenkään ollut hyvä idea? (negative)
Wasn't this a good idea after all?
"It might have seemed like a good idea, but now I think it might have been a bad idea."

Like in English, there are environments where negative polarity items can appear in affirmative sentences and vice versa (some examples):

Hänellä tuskin on harmaintakaan aavistusta.
He barely has any idea.
Vain harva enää uskoo, että ongelmaa voidaan ratkaista millään keinolla.
Only few now think there is any solution to the problem.
Ei minua haittaisi saada jotakin vaativampaa työtehtävää.
I wouldn't mind some more challenging task.
Nyt, jos koskaan, on aika tarttua toimeen.
Now, if ever, is the time to take action.
Elokuva oli parempi kuin odotinkaan.
The movie was better than I expected.