The syntax of predicative nominals and predicative adjectives in ancient IE languages and, as far as I know, almost every modern one :

Subject (NOMINATIVE) + copula + predicate (NOMINATIVE)

In modern Polish and Russian (and on that basis I assume all Slavic although I do not have solid information on that) the same construction looks like this:

Subject (NOMINATIVE) + copula + predicate (INSTRUMENTAL)

I don't know about Russian, but in Polish this applies only to predicative nominals. In the predicative adjectives the predicate stands in nominative like expected. Although this is not the case in the Polish literature from the first half of the XX century where the instrumental construction very often appears also in predicative adjectives.

My question is : what is the origin of the instrumental case of the predicate in predicate nominals and adjectives in these languages?

3 Answers 3


In Russian, instrumental case applies only for past/future tenses, never for present tense (if by "copula" we mean "to be" only; Ukrainian, on the other hand, allows it in present tense as well, but I think it's an influence from Polish). I suspect copula+INSTR could arise from interference with other static verbs of "being", where instrumental is normal, for example, Russian kazats'a + INSTR "to appear as X". In Czech, there used to be a rule (IIRC not enforced today much): INSTR meant temporal being, something like, "I'm a teacher" (I work as a teacher) while NOM meant something which never changes, I don't know, "I'm a man". The interference: "I work as a teacher (INSTR)" => "I'm a teacher" (INSTR)

Why INSTR (and not any other case) is used with verbs like "to appear", "to look", "to become" etc. -- is a different question I don't know the answer for.

(I don't know the whole picture myself, just shared what I know, I hope it's helpful.)

  • 1
    the latter-day pseudo-copula являться does take instrumental in the present. Aug 17, 2015 at 19:07
  • 1
    Also, it's important to note that a case called instrumental had existed in Proto-Slavic and its descendants long before people decided to call it instrumental, and so its "eponymous" function is not necessarily a factor when considering the (clearly very old) usage of this case with verbs for being, becoming, appearing, etc. Finnish has a dedicated case called essive, for exactly that scope of meanings; so to borrow a useful term, I'd say the Slavic instrumental is just as much of an "essive" — and ultimately, it is itself, and transcends whatever name we might give it. Aug 17, 2015 at 19:12
  • My guess is, any stative verb takes a predicate noun in the same way as "to be".
    – Spencer
    Jul 17, 2022 at 22:23

The question worth asking here is, how "instrumental" is the Slavic instrumental really? "Instrumental" is just a name that grammarians gave it, after its most common usage; but I don't think the pre-literate speakers of Proto-Slavic would think of it as a case for expressing instrumentality. To them, it just was what it was. The case for instruments and passive-sentence agents, as well as the case for times of day/year, as well as the case required by the prepositions for "behind" and "in front of", as well as the case for being or becoming, as well as the case for modes and manners (every -sky adverb in every Slavic language is historically an instrumental, plural, neuter adjective. По-русски is a technically ungrammatical contamination of rusьsky with po rusьsku.) And that latter meaning can probably elucidate how instrumental "felt" to speakers of Proto-Slavic — as a "modes and manners" case, which could equally be modes of doing — as in *maltomъ "with a hammer" or *slověnьsky "in Slavic", "the Slavic way" — or modes of being, as in *byti dobryjimъ "to be good". Or circumstantial modes such as *noktijǫ "at night".

  • 1
    It is interesting but I don't see how is it relevant to the question I asked. It could be also stated as " What is the origin of the other than nominative case of predicate in predicative nominals in Polish/Russian ". The thing that makes me curious in the first place is the question of why this syntax shifted from the NOM NOM one to NOM (different case) one. This other case just turns out to be instrumental, and of course we can include its features in the search for the reason of that syntactic change but in the end this is not a study about instrumental case and history of its usage.
    – czypsu
    Aug 17, 2015 at 22:37
  • Interesting. What if we saw the "instrumental" function, as well as some of the others, as somehow derived from an earlier comitative, hence "accompaniment" / "presence" / "proximity" of somebody or something? I've always thought the connection between comitative and instrumental meanings is notoriously widespread, cf. the German preposition mit, whose function is both, if I'm not mistaken. Aug 17, 2015 at 22:45
  • @Nikolay Ershov I see your answer like a comment that could be added below either of the posts. ( as it actually also is right now )
    – czypsu
    Aug 17, 2015 at 22:45
  • @PavelJetušek and English "with" ? If I am analysing properly, it ,alongside "by", is used to indicate instrumentality and in addition presence/proximity that you mentioned.
    – czypsu
    Aug 17, 2015 at 22:50
  • Ah, yes, of course. Why didn't I come up with that myself? Aug 17, 2015 at 22:53

To begin with, it might be a Circum-Baltic areal feature we could call marked predicative construction (as opposed to the unmarked/less marked nominative/accusative), as the following source suggests: On the marking of predicate nominals in Baltic. Whether the Slavic languages were the first ones to acquire this construction, which later spread further, I'm not sure, but here's an idea that has just occured to me:

As the instrumental is (at least in Czech) used to mark the agent of a passive clause, such as...

Jan byl zabit vrah-em.
Jan.NOM was killed murderer-INST.
"Jan was killed by a murderer." (INST obligatory)

...I'm beginning to wonder whether the predicative instrumental construction could have arisen through a shift in agentivity - of sorts. I'm only trying to catch a glimpse of something that's just evading my mind now, really, but the notion of temporariness or changeability in the instrumental constructions as opposed to a relatively greater stability in the nominative constructions also seems to evoke the notion of dynamicity as opposed to stativity in a way. A look at the following examples in Czech might elucidate what I mean:

1a. Učinil-i Jen-a.
    Made.3PL Jan.ACC.
    "They made Jan."

1b. Učinil-i učitel-e.
    Made.3PL teacher-ACC.
    "They made a teacher."

2.  Učinil-i Jen-a učitel-em.
    Made-3PL Jan.ACC teacher-INST
    "They made Jan a teacher."

3.  Učinil-i z Jen-a učitel-e.
    Made-3PL from Jan.GEN teacher-ACC.
    "They made a teacher from Jan."

Cf. the passive:

4a. Jan byl učiněn [jimi].
    Jan.NOM was made [they.INST].
    "Jan was made [by them]."

4b. Učitel byl učiněn [jimi].
    Teacher.NOM was made [they.INST].
    "The/A teacher was made [by them]."

5.  Jan byl učiněn učitel-em [jimi].
    Jan.NOM was made teacher.INST [they.INST] (potential ambiguity)
    "Jan was made a teacher [by them]."

Notice also...

6a. Jan je učitel-em.
    Jan.NOM is teacher.INST.
    "Jan is a teacher (now, perhaps temporarily, maybe not for real)."

6b. Jan se stal učitel-em.
    Jan.NOM became teacher.INST.
    "Jan became a teacher." (INST required, irreplaceable by NOM here)


7a. Z Jen-a je učitel.
    From Jan.GEN is teacher.NOM.
    (=6a approximately)

7b. Z Jen-a se stal učitel.
    From Jan.GEN became teacher.NOM
    (=6b approximately)

Hence, I'm picturing something like the following:

Jan's been made a teacher-INST. Jan is a teacher-INST.

As if a non-subject agent (or the more agentive-ish non-subject), unless made oblique by an intervening preposition, required the instrumental by default, originally, perhaps, in the passive only (?), then (?) in other contexts too?

The agentivity shift (if that's the right way to call it) is just a spontaneously materialized idea, really, but somehow I can't stop feeling that the two phenomena are connected in one way or another. I'll definitely keep thinking about this issue.

  • 1
    I need to carefully process all that, but for now, just one quick thing to add. In Polish the usage of cases in the situations you described and exemplified looks exactly the same with one exception. The agent in passive clause is never expressed simply by INST. This is done with a prepositional construction - "przez" + agent.ACC . Jan był zabity przez mordercę - Jan.NOM was killed by a murderer.ACC
    – czypsu
    Aug 17, 2015 at 22:27
  • 1
    Intriguing! So, there's an accusative-requiring preposition that intervenes when the agent is human, right? Or is the constraint more specific, say, whn the agent is masculine-animate? Sorry, my Polish is too rudimentary. Aug 17, 2015 at 22:51
  • Hmm. It can be also used for inanimate agents. But in that case both constructions, prepositional and instrumental, can be used. Sorry for the confusion in previous comment, I have hard time analysing Polish being my native language. To conclude : animate agent - only prepositional construction, inanimate agent - prepositional or instrumental construction. You can say either " Jan był zabity krzesłem.INSTR "or "Jan był zabity przez krzesło.ACC" but "Jan był zabity mordercą.INSTR" sounds unnatural and incorrect.
    – czypsu
    Aug 17, 2015 at 23:01
  • But then, when I start to think about this instrumental construction with inanimate agent it appears to me as being not the same category as the prepositional one. I am sorry I can't describe it in an adequate way, that is just my native's perception. The instrumental construction sounds and looks like a mix of one solid passive clause " Jan był zabity" with an optional adverbial "krzesłem.INSTR". On the other hand the prepositional construction seems more coherent in some way , more bound together.
    – czypsu
    Aug 17, 2015 at 23:06
  • I have just realised that you can produce this grammatical and correct sentence : "Jan był zabity przez mordercę krzesłem". And there's is absolutely no ambiguity. The agent is clear, which is "morderca", and "krzesło" is just an instrument, a way of action, adequately used in INSTR. I would say that instrumental is not intensifying agentivity, it works on slightly different level which secondarily can also be used to indicate agent.
    – czypsu
    Aug 17, 2015 at 23:23

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