Detail #15: Non-trivial Verbal Discongruence

Discongruence is a thing that really interests me. Congruence, of course, is a rather obvious way of increasing redundancy in a language. Marking gender on verbs or adjectives, case on adjectives as well as nouns, gender on both adjectives and nouns [...] are all ways of having some information appear twice or having some extra information appear that may help in case noise appears along the line (which it will).

Some languages have weird discongruences though, such as the Semitic inverse gender marking with some numbers. Some languages have a bunch of set phrases (or half-set, as the construction type may be somewhat productive): Finnish has a bunch of adjective + noun phrases where the adjective is in nearly any of the spatial + role-related cases and the noun is in either the partitive or the instructive (= instrumental) case. Pitkäksi aikaa = long.translative time.part = for a long time, tällä tavoin = this.allative manner.instrument = by this manner, in this manner, like this (adverbial).

Further, some languages permit some discongruence in the verb phrase, like having the verb sometimes be third-person singular rather than the proper, expected person marking (even when not counting things like quirky-case subjects not triggering congruence for their person, or whatever along those lines). I find it likely most languages that do stuff like that tend to permit third person verb marking for non-third person subjects, but how about a language where this is not the case - where any person can get any person's verb marking under some circumstances, like, some lexically determined verbs that just *permit that kind of thing* or with certain phrases or whatnot? (Note: English dialects where the congruence system doesn't line up with standard English verb morphology are not an example.) Preferrably, the exceptional markings should occur seldom enough that they don't affect the default interpretation of the suffixes, but often enough that they are learned and could be part of the language for a wide speech community.