Detail #126: Things inspired by negation

Some languages have a negative auxiliary that carries the person marking (and in some, TAM, etc). How about widening this up a bit?

• regular congruence on the main verb, used with most positive statements
• negative auxiliary + infinitive or some other 'less' finite verb form*, used with negative forms
• non-negative auxiliary + infinitive or some other 'less' finite verb form - here's the interesting bit

The non-negative auxiliary is used for positive answers to negative questions, after conjunctions when the speaker wants to mark a contrast or something unexpected (so, along the line of 'but', 'although', 'even though', etc).

* Finnish uses a form that is morphologically identical with the singular imperative in the non-past tense, and a form that is identical with the active past participle in the past tense. The passive has its own conegative forms as well, which correspond to passive participles in the past tense, but to a slightly shortened form in the non-past. C.f. 'olla', to be - carefully note that the Finnish passive is not a 'true' passive that demotes subjects and promotes objects, but rather similar to the German 'man' pronoun in its use:
olen - en ole, (I am, I am not)
olin - en ollut, (I were, I were not)

olen ollut, en ole ollut (I have been, I haven't been)

olin ollut, en ollut ollut (I had been, I had not been)
ollaan, ei olla (is-passive, is-passive not; the form obtained by cutting off the -an)

oltiin, ei oltu (were-passive, were-passive not)

on oltu, ei ole oltu (has been-pass, has not been-pass)