Slovak: optional uses of the instrumental case with "to be"

[Londyncan69]

When learning basic Slovak, my understanding was that people might refer to their occupation using the instrumental case and "to be", but the instrumental case seems to be more widely used as the complement of the verb "to be", both when referring to people and countries from what I can see. It is even used in place of the subject of the verb.

Some examples where the instrumental case is used as the complement of “to be”

Arcivojvoda Otto bol synom posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.
Je úžasný a dúfame, že bude príkladom pre mnohých ľuďí! (of a person)

Irsko je prvou krajinou Unie, ktora schvalila jednotny dizajn cigaretovych skatuliek.
Slovensko je zaujímavou destináciou pre Maďarov

Some very similar sentences where the nominative case is used

Otto Habsburg-Lothringen, bol najstarší syn cisára Karola I. a bývalý korunný princ Rakúsko-uhorskej monarchie,

Holandsko je prvá krajina, ktorá prijala zákon osieťovej neutralite.
Slovensko je ideálna destinácia pre Britov - Slovensko je ideálne miesto pre Britov na dovolenku.

Some examples of the use of instrumental case as the subject of the verb “to be”

Som lišiak. Mojou misiou je priniesť vám lepšie bývanie.
JazzVideo Guy: Mojou misiou je zabrániť tomu, aby sa jazz stal neviditeľným

Some very similar sentences where the nominative case is used

Snowden: Moja misia je už ukončená
Tretí televízny cyklus Moja misia je na svete

I can see from a previous thread on this forum that there is talk of the instrumental case expressing a temporary or subjective opinion whereas the nominative denotes a permanent quality or undisputable fact (in both Czech and Slovak).
Source: Slovak: učiteľ[om], 29 April 2013. As a new member I'm not allowed to post a link to a webpage but a Google search for Wordreference thread 2627170 will pick this up.

Likewise there is another thread which suggests that when the nominative case is used with “to be” in Czech it expresses inherent nature and the instrumental expresses transient function.
Source: Instrumental case + být. Wordreference thread 1715855.

A third thread suggests that in Polish, referring to professions using the instrumental case is more formal and using the nominative case is informal or regional.
Source: Use of instrumental for. Wordreference thread 2507857.

However, my examples don't involve professions. And, also, I am looking at attributes such as being the son of someone which do not seem to be temporary qualities. And even with being the first country to achieve a particular distinction, where you might use the verb "become" with the instrumental case, how is it that the instrumental and nominative are pretty much interchangeable with the verb "to be"?

Some questions I have about the Slovak examples above are:

1. When and why is the instrumental used rather than the nominative case?
2. What can one say about this usage more generally?
3. Is it becoming more widespread and does it form part of a trend?
4. How long has it been going on?

Any help gratefully received.

 

[francisgranada]

Let's see the further development of this thread, at moment only some observations:

... Moja misia je už ukončená
Tretí televízny cyklus Moja misia je na svete ...

In these examples only the nominative case is possible.

I can see from a previous thread on this forum that there is talk of the instrumental case expressing a temporary or subjective opinion whereas the nominative denotes a permanent quality or undisputable fact ...

It seems to be a bit more "complicated". In your example "Arcivojvoda Otto bol synom posledného rakúskeho cisára .. ", Otto was permanently and indisputably (as far as we know ) the son of the last emperor.

Perhaps, when the function/status/position/charge ... of someone is being emphasised, then the instrumental case is preferable (at least in the written language). E.g. "Obama je prezidentom USA" (= he has the charge/status of the president). In case of the previous example with "arcivojvoda Otto", rather his status/position of being the son of the Austrian emperor and Hungarian king is emphasised/focused. But this is rather an idea of mine, not a "rule" ...

 

[Londyncan69]

Let's see the further development of this thread, at moment only some observations:
In these examples only the nominative case is possible.
It seems to be a bit more "complicated". In your example "Arcivojvoda Otto bol synom posledného rakúskeho cisára .. ", Otto was permanently and indisputably (as far as we know ) the son of the last emperor.

Perhaps, when the function/status/position/charge ... of someone is being emphasised, then the instrumental case is preferable (at least in the written language). E.g. "Obama je prezidentom USA" (= he has the charge/status of the president). In case of the previous example with "arcivojvoda Otto", rather his status/position of being the son of the Austrian emperor and Hungarian king is emphasised/focused. But this is rather an idea of mine, not a "rule" ...

Thanks very much for your input here and about regional variants of päťtisíc.

“Mojamisia je” and “mojou misiou je”

I am curious as to why in two sentences only “moja misia” is possible whereas in the two others “mojou misiou” can be used. Is it anything to do with it being a completed or ongoing mission? Or is it the case that the "mojou misiou" sentences are followed by an infinitive and the "moja misia" sentences are not?

When I look for more examples of "mojou misiou" as the subject of "to be", mostly I do find them to be followed by an infinitive. For example:

Novýšéf RTVS Mika: Mojou misiou nie je šetriť
"Mojou misiou je ničiť iné týmy."
„Mojou misiou je ísť na sever, braček," povedal Ran Gereset.

But I can also find “moja misiou” followed by the nominalisation of a verb (riešenie).

V politike som štyri roky a mojou misiou je riešenie problémov mladých rodín.

And even followed by a simple noun (práca).

Som rehoľná sestra Služobnica Ducha Svätého a mojou misiou je práca v Štátnej nemocnici ako kaplán.

When I go looking for more examples of “moja misia je”, I find that it is more likely to be followed by something other than an infinitive,e.g. an adjective. For example:

Prvá moja misia je orientovanána dobro pre ľudí.
Moja misia je splnená
Moja misia je teraz vo vlastnej rodine a v práci.

But I also find plenty of cases with the infinitive:

Moja misia je robiť rap. Už dva roky som v tejto hre.
Moja misia je šíriť monoteizmus (vieru, že existuje iba jeden Boh) na každom mieste na tejto Zemi.
Moja misia je vyliečiť svet z choroby „SDHD“

Generalisations about the instrumental case from other Slavic languages

I can also, as you say, definitely see that being the son of the emperor is a political role as well as being a permanent family relationship.

The strange thing about the two examples involving Otto Habsburg, where one uses the instrumental „je synom cisára”and the other uses the nominative „je syn cisára”to denote the same attribute, is that they both come from the same article: a Slovak Wikipedia entry on the son of the last emperor.

I've been doing more online research and there is a fairly detailed discussion of “to be” plus the instrumental in Czech, Polish and Russian on page 98 of The Chain of Being and Having in Slavic by Steven J Clancy. As a newbie, I can't a post a weblink on this forum but if you type "instrumental byt” into Google Books it can be found easily.

This book says that the use of the instrumental predicate is more common in Polish and Russian than Czech (and in Russian is used with the past and future but not present tense). In Czech, this usage of the instrumental is associated with the literary language but infrequent in speech. Again, it is said that in Czech the instrumental is associated with temporary and acquired qualities whereas the nominative is associated with permanent or inherent qualities.

There is also an interesting section on the use of the instrumental with“to be” in a book chapter “Nonverbal predication in the Circum-Baltic languages” by Leon Stassen. This appears from page 577 of The Circum-Baltic Languages: Grammar and Typology, edited by Osten Dahlet. al. This can again be found in Google Books searching for“instrumental byt”.

The book chapter predominantly deals with Russian but it also deals with Latvian, Lithuanian, and Polish from page 573, and says that its main points are generalisable from Russian to other Slavic languages. About Russian, it says:

• Some authors identify the permanency-contingency distinction as a prime mover of a switch from nominative to instrumental.
• However, a classic study of nominative predicates in Russian concludes that the switch from nominative to instrumental “must be seen as resulting from the interaction of a set of independent parameters and that no single determinant factor can be identified. These parameters hail from different domains and levels of grammar, such as lexical semantics, style and contextual circumstances.”
• In Russian, the predicate of to be is preferably instrumental and under negation this may even be obligatory.
• In Russian, as a matter of style, the instrumental predicate is more prestigious than the nominative.
• In Russian, descriptive or characterising words such as “fool” prefer the nominative whereas words which indicate function, role or occupation such as “teacher” prefer the instrumental.
• In Russian, the instrumental may encode an aspectual difference, indicating habitual aspect or the pluperfect “used to be” and “was but no longer is”.

The author says that Baltic and Balto-Finnic languages have a firmer distinction between these two ways of encoding predicates, based upon relative time-stability. But the Slavonic languages of this area, in general, tend to blur the distinction “to the point that double encoding tends to serve mainly as the expression of modal-aspectual,as well as sociolinguistic and stylistic nuances”.

The author also says that “the blurring of semantic motivations for double encoding into a vague, stylistic opposition is a general and presumably natural phenomenon which can be observed widely in different language areas”.

So, if the conclusions of studies of Czech, Russian, and other Slavic languages are generalisable to Slovak, it may be that:

• There is no single factor determining whether to use the nominative or instrumental. Usage is, at least in part, a matter of style.
• The instrumental is associated with acquired, temporary, functional and occupational characteristics and the nominative with inherent and permanent characteristics.
• The instrumental is associated with formal and literary usage and the nominative with informal speech.

I don't have enough exposure to the Slovak language to know whether this is true but it's an interesting hypothesis for the use of the instrumental in adjectival and noun predicates with “to be”.

Having said that, the hypothesis doesn't quite cover the use of the instrumental as the subject of “to be” which appears to be more limited than the predicative uses. So you can have “mojou misiou” as the subject of “to be” but not, apparently, “synom cisára“.

 

[morior_invictus]

Nominativ podstatného mena vyjadruje, že daný predmet je bez vzťahu k inému predmetu alebo deju, a má svoj základný výpovedný zmysel ako základ jednočlennej vety. Z hľadiska výpovede a jej cieľa je nominativ v jednočlennej vete sebestačný, úplný, netreba z neho prejsť k prísudku. Nominativ podstatného mena tu stačí na vyjadrenie istej skutočnosti a na dosiahnutie dorozumievacieho cieľa v danej situácii. Morfologicky je tento nominativ čisto pomenovaním predmetu bez vzťahu k iným predmetom a javom. Jeho zmysel ako samostatnej výpovede spočíva v tom, že je súčasne rámcom výpovede i výpovedným obsahom v tomto rámci.
Obsahový nominatív býva predovšetkým prísudkom pri sponovom slovese byť (zriedka i pri slovese ostať): Jakub Gríľa bol už starý chlap, (MINAč) [...] Proti prísudkovému inštrumentálu vyjadruje tento nominatív trvalý, podstatný príznak, ktorý vyčerpáva podstatu kvalifikovaného predmetu. Preto sa používa najmä v definíciách: To je veľká vec. (TATARKA) Pri identifikácii: Nechaj ho. To je krt. (ONDREJOV) A konečne ako výrazová zvláštnosť: Láske je bieda chiméra, (SLáDKOVIč)
Vo voľnom postavení pri prísudku má nominatív funkciu doplnku: Chlap je to dobrák.
[...]
Inštrumentál Z celostného významu prechodnej účasti deja na danom predmete pri inštrumentáli vyplýva, že vyjadruje v prvom rade okolnostné významy miesta, času, nástroja, prostriedku, pôvodcu, príčiny a zreteľa. Z nich sú odvodené jednak kvalifikačné významy spôsobu (miery a účelu), prísudku a doplnku, jednak objektové významy prechodného, výlučného, stavového, obsahového a výsledkového objektu.
Prísudkový a doplnkový inštrumentál Vyjadruje menný obsah predikácie pri slovesách so všeobecným významom, ako sú byt, stať sa, stávať sa, ostať, ostávať, zostať, zostávať; tváriť sa, ukazovať sa, robiť sa, zdať sa, prejaviť sa, cítiť sa, pripadať si, vidieť sa. Je synonymný s prísudkovým nominatívom, proti ktorému vyjadruje prechodný, časovo alebo ináč aktualizovaný príznak (Katka je šikovná balička — Katka je v továrni baličkou):

Source : Morfológia slovenského jazyka. p. 158-59, 189-190
As for your examples, here's my take on them:

Arcivojvoda Otto bol synom posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.
Arcivojvoda Otto bol syn posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.

Je úžasný a dúfame, že bude príkladom pre mnohých ľuďí!
Je úžasný a dúfame, že bude príklad pre mnohých ľuďí!

Irsko je prvou krajinou Unie, ktora schvalila jednotny dizajn cigaretovych skatuliek.
Irsko je prvá krajina Unie, ktora schvalila jednotny dizajn cigaretovych skatuliek.

Slovensko je zaujímavou destináciou pre Maďarov.
Slovensko je zaujímavá destinácia pre Maďarov.

Otto Habsburg-Lothringen bol najstarší syn cisára Karola I. a bývalý korunný princ Rakúsko-uhorskej monarchie. NOT OK
Otto Habsburg-Lothringen bol najstarším synom cisára Karola I. a bývalým korunným princom Rakúsko-uhorskej monarchie. OK

Holandsko je prvá krajina, ktorá prijala zákon osieťovej neutralite. OK
Holandsko je prvou krajinou, ktorá prijala zákon osieťovej neutralite. OK

Slovensko je ideálna destinácia pre Britov - Slovensko je ideálne miesto pre Britov na dovolenku. NOT OK
Slovensko je ideálnou destináciou pre Britov - Slovensko je ideálnym miestom pre Britov na dovolenku. OK

Som lišiak. Mojou misiou je priniesť vám lepšie bývanie. OK
Som lišiak. Moja misia je priniesť vám lepšie bývanie. INCORRECT

JazzVideo Guy: Mojou misiou je zabrániť tomu, aby sa jazz stal neviditeľným. OK
JazzVideo Guy: Moja misia je zabrániť tomu, aby sa jazz stal neviditeľným. INCORRECT

Snowden: Moja misia je už ukončená OK
Snowden: Mojou misiou je už ukončená INCORRECT

Novýšéf RTVS Mika: Mojou misiou nie je šetriť OK
Novýšéf RTVS Mika: Moja misia nie je šetriť INCORRECT

"Mojou misiou je ničiť iné tímy." OK
"Moja misia je ničiť iné tímy." INCORRECT

„Mojou misiou je ísť na sever, braček," povedal Ran Gereset. OK
„Moja misia je ísť na sever, braček," povedal Ran Gereset. INCORRECT

V politike som štyri roky a mojou misiou je riešenie problémov mladých rodín. OK
V politike som štyri roky a moja misia je riešenie problémov mladých rodín. INCORRECT

Som rehoľná sestra Služobnica Ducha Svätého a mojou misiou je práca v Štátnej nemocnici ako kaplán. OK
Som rehoľná sestra Služobnica Ducha Svätého a moja misia je práca v Štátnej nemocnici ako kaplán. INCORRECT

Prvá moja misia je orientovaná na dobro pre ľudí. OK
Prvou mojou misiou je orientovaná na dobro pre ľudí. INCORRECT

Moja misia je splnená OK
Mojou misiou je splnená INCORRECT

Moja misia je teraz vo vlastnej rodine a v práci. OK
Mojou misiou je teraz vo vlastnej rodine a v práci. INCORRECT

Moja misia je robiť rap. Už dva roky som v tejto hre. INCORRECT
Moja misia je šíriť monoteizmus (vieru, že existuje iba jeden Boh) na každom mieste na tejto Zemi. INCORRECT
Moja misia je vyliečiť svet z choroby „SDHD“ INCORRECT

 

[francisgranada]

I am curious as to why in two sentences only “moja misia” is possible whereas in the two others “mojou misiou” can be used. Is it anything to do with it being a completed or ongoing mission? Or is it the case that the "mojou misiou" sentences are followed by an infinitive and the "moja misia" sentences are not?

The instrumental case cannot be used to denote directly the quality using an adjetive (ukončená) or the location (na svete) of the subject. It's used rather in cases that express grosso modo the idea of "doing something" (infinitive) or "being something/someone" (noun). In the two examples mentioned above the usage of the instrumental case would be not only unused or unnatural, but also aggrammatical.

For sake of the discussion, I'd like to know the opinion of the natives, i.e. if they feel any difference between the nominative and instrumental in the following examples and which one wouldn't they use at all:

Môj otec je riaditeľ.
Môj otec je riaditeľom.
Môj otec je riaditeľom školy.

Riaditeľ je môj otec.
Riaditeľ je mojim otcom.

Peter je môj priateľ.
Peter je mojim priateľom.
Peter je môj priateľ z detstva.
Peter je mojim priateľom z detstva.

Môj priateľ je Peter.
Môj priateľ je Petrom.

 

[Sobakus]

It's important to note that a subject can never be expressed by the Instrumental. The relatively free word order of Slavic allows it keep the topic-comment and subject-predicate distinctions separate, thus it's possible to place the topic-predicate mojou misiou je in front of the comment-subject práca and so change the information structure without changing the grammar or, conversely, change the grammar without changing the information structure.

Along those lines, I'd like to ask the natives if Moja misia je/bola neľahkou is possible in Slovak (it's preferred in Russian in the Past or Future).

 

[Enquiring Mind]

Very interesting thread, thanks for all the detailed research.

Riaditeľ je mojim otcom.Môj priateľ je Petrom.

These, I (non-native) think, are absolutely impossible by the criterion of the "temporary versus permanent characteristic" or "intrinsic/non-intrinsic" or "defining/non-defining" - justify it in whichever way you choose - trvalý, podstatný príznak as described in #4 - thank you MI!

My father is the permanent, intrinsic and invariable characteristic. There's no way that being a driver can be more intrinsic to who that person is than him being my father.
Same with Peter. He is Peter permanently. That is an intrinsic and unalterable part of who he is. The characteristic of being my friend is impermanent, temporary, non-intrinsic to Peter. It doesn't define him as a person.

Along those lines, I'd like to ask the natives if Moja misia je/bola neľahkou is possible in Slovak (it's preferred in Russian in the Past or Future).

Sorry, not a native (but lots of professional exposure to Slovak), but I think the instrumental in this specific grammatical construction is not possible in Slovak in any tense.

 

[francisgranada]

It's important to note that a subject can never be expressed by the Instrumental ...

I agree, or in other words, I've "problems" to perceive/accept nouns in instrumental as subjects ...

... Along those lines, I'd like to ask the natives if Moja misia je/bola neľahkou is possible in Slovak (it's preferred in Russian in the Past or future).

Regardless of what is considered "officially" correct or incorrect, my personal answer is that I feel some difference, i.e. even if (spontaneousely/probably) I wouldn't use the instrumental in your examples, in case of past and future tenses the instrumental "sounds better" (more acceptably, depending on the context, of course). I've consulted also a person of Slovak mother tongue, coming from a Middle Slovakian linguistic area - she has the same "feeling".

... My father is the permanent, intrinsic and invariable characteristic. There's no way that being a driver can be more intrinsic to who that person is than him being my father. Same with Peter. He is Peter permanently ...

Again, regardless of what is considered correct (or "logic"), I have the opinion/impression that for "Riaditeľ je mojim otcom" (or "Mojim otcom je riaditeľ) it's more probable to find a "fitting" context than for "Môj priateľ je Petrom" (i.e. the latter doesn't sound good, while the former "could be" acceptable). Confirmed also by the person mentioned before.

 

[Londyncan69]

It's important to note that a subject can never be expressed by the Instrumental. The relatively free word order of Slavic allows it keep the topic-comment and subject-predicate distinctions separate, thus it's possible to place the topic-predicate mojou misiou je in front of the comment-subject práca and so change the information structure without changing the grammar or, conversely, change the grammar without changing the information structure.

Along those lines, I'd like to ask the natives if Moja misia je/bola neľahkou is possible in Slovak (it's preferred in Russian in the Past or Future).

Thanks for this helpful contribution.

As a native-English speaker I fell into the trap of allowing word order to unconsciously influence my judgment of what was the subject of the sentence and what wasn't.

I now recognise “mojou misiou je” as a predicate located at the beginning of the sentence, something that would be unusual, and most probably poetic, in English. And I can see that “moja misia je” can be the subject of the sentence, of necessity in the nominative case (although I have wondered whether it is also sometimes used as a predicate formed by words in the nominative case).

One useful test for me after realising this is to reread my examples and ask whether the phrase that comes after “Mojou misiou je/moja misia je” could be the subject of the sentence.

Take the first two examples I found:

Som lišiak. Mojou misiou je priniesť vám lepšie bývanie.
JazzVideoGuy: Mojou misiou je zabrániť tomu, aby sa jazz stal neviditeľným

It is clear here that the phrase “priniesť vám lepšie bývanie" is treated by the writer as the subject of the sentence. As is "zabrániť tomu, aby sa jazz stal neviditeľným". It appears that these phrases beginning with an infinitive act like a noun in the nominative case. Having “mojou misiou je” as a predicate in the instrumental case makes sense as a mission may be an acquired or even temporary characteristic rather than something inherent or permanent.

The next two examples I found were:

Moja misia je už ukončená
Tretí televízny cyklus Moja misia je na svete

It is clear here that “ už ukončená” or “na svete” couldn't be the subject of a sentence, as francisgranada points out above. It makes no sense for an adjective or an adjectival phrase in the locative case to be the subject of a sentence and therefore “je moja misia” would appear obligatory.

If you look at the additional examples I found, it makes sense for the nouns in the nominative case (práca, riešenie) to take “je mojou misiou” as a predicate formed of words in the instrumental case. So you have:

Mojou misiou je riešenie problémov mladých rodín.
Mojou misiou je práca v Štátnej nemocnici ako kaplán.

And as it doesn't make sense for standalone adjectives or adjectival phrase to be the subject in other example sentences that I found, they must be the predicate that goes with “je moja misia”. So you have:

Prvá moja misia je orientovaná na dobro pre ľudí.
Moja misia je splnená
Moja misia je teraz vo vlastnej rodine a v práci.

With that cleared up for me, there's still a puzzle. I find that phrases beginning with an infinitive are treated both ways - sometimes with "mojou misiou je" and sometimes with "moja misia je".

Here are the examples I found where the phrase beginning with the infinitive is treated as the subject of the sentence, taking "mojou misiou je":

Nový šéf RTVS Mika: Mojou misiou nie je šetriť
"Mojou misiou je ničiť iné tímy."
„Mojou misiou je ísť na sever, braček," povedal Ran Gereset.

And here are the other examples.

Moja misia je robiť rap.
Moja misia je šíriť monoteizmus na každom mieste na tejto Zemi.
Moja misia je vyliečiť svet z choroby „SDHD“

In these cases it looks to me like one of two things could be going on. Either the phrase beginning with an infinitive is treated as the predicate with "moja misia je" as the subject, of necessity in the nominative case. Or, the phrase beginning with an infinitive remains the subject of the sentence but it has a predicate "moja misia je" composed of words in the nominative case. This would give it the same grammatical form as the sentence "netball je prevažne ženský šport" where both subject and predicate are composed of words in the nominative case.

So why do phrases beginning with an infinitive take either "moja misiou je" or "moja misia je"? Is the choice of one over the other a matter of style and emphasis or is one a mistake?

I can't see that the verbs in the infinitive in one set of examples above involve missions that are more or less permanent or inherent than the verbs in the infinitive in the other set of examples. If they were, that might - somewhat tenuously - explain why mission as a noun could either be in the nominative or instrumental case with "to be". And if it were the case that use of the instrumental was more formal than use of the nominative, it isn't obvious that "Mojou misiou je ničiť iné tímy" is more suited to formal language than “Moja misia je šíriť monoteizmus”. Although, more plausibly, it may be the speaker's desire for formality, rather than the subject matter, that determines whether the formal variant is used.

When I look at the opinion morior_invictus, as a native Slovak speaker, has very helpfully given on the all the examples involving moja misia/moja misiou, all the adjectives and adjectival phrases are felt to require “moja misia je” and all the nouns in the nominative case are felt to to require “mojou misiou je”. This is perfectly in line with the actual usage I found in my examples, which are taken from online newspapers/websites.

Moriur_invictus also treats all the examples which have phrases beginning with an infinitive as instances where that phrase is the subject of the sentence, requiring “mojou misiou je”. It is felt that the other examples are incorrect usage when they either treat the phrase beginning with an infinitive as the predicate of "moja misia je" or treat the phrase beginning with an infinitive as the subject with "moja misia je" as a predicate composed of words in the nominative case.

That's interesting.

Thanks to everyone for helping with this.

 

[morior_invictus]

Prvá Moja prvá misia je orientovaná na dobro pre ľudí. ----> the sentence as such is, however, still awkward ("na dobro pre ľudí" )

And here are the other examples.

Moja misia je robiť rap. This sentence is constructed in the following way - Moja misia: robiť rap. / Moja misia = robiť rap. but I don't like any of those three sentences. They sound terrible to me as they stand. In that case, your dilemma might be completely solved.
Moja misia je šíriť monoteizmus na každom mieste na tejto Zemi.
Moja misia je vyliečiť svet z choroby „SDHD“

And if it were the case that use of the instrumental was more formal than use of the nominative, it isn't obvious that "Mojou misiou je ničiť iné tímy" is more suited to formal language than “Moja misia je šíriť monoteizmus”. Although, more plausibly, it may be the speaker's desire for formality, rather than the subject matter, that determines whether the formal variant is used. It has nothing to do with formality.

P.S.: I, as EM, would put to "Riaditeľ je mojím otcom." and "Môj priateľ je Petrom." and also to "Moja misia je/bola neľahkou." (Moja misia sa stala neľahkou. is fine, though. But then, it is not an example of the "X to be Y" construction so it is ruled out as immaterial).

As for the examples given by francis, welllll. . .

Môj otec je riaditeľ. NOT GOOD, AS IT STANDS
Môj otec je riaditeľom.
Môj otec je riaditeľom školy.

Riaditeľ je môj otec.
Riaditeľ je mojim otcom. ERM... NOT GOOD (Mojím otcom je samotný riaditeľ nadnárodnej spoločnosti. GOOD WHEN USED AS AN EMPHASIS)

Peter je môj priateľ. OK
Peter je mojim priateľom. NOT GOOD, AS IT STANDS
Peter je môj priateľ z detstva. OK
Peter je mojim priateľom z detstva. ERM... (Peter je už od detstva mojím priateľom a ostane ním aj naďalej. OK)

Môj priateľ je Peter. AWKWARD
Môj priateľ je Petrom. COMPLETELY WRONG

Other foreros may feel differently.

 

[Sobakus]

Or, the phrase beginning with an infinitive remains the subject of the sentence but it has a predicate "moja misia je" composed of words in the nominative case. This would give it the same grammatical form as the sentence "netball je prevažne ženský šport" where both subject and predicate are composed of words in the nominative case.

But it is the same grammatical construction – in line with this thread, it can also theoretically be "... je prevažne ženským športom." Or you could change the word order to mirror that of the phrase in question: "prevažne ženským športom je netball". The way to tell the subject in somewhat unclear cases like this one is to simply change the verb to one with different case agreement – it's the predicate that will have to change its case. In our example, you don't even have to change the verb.

 

[francisgranada]

Môj priateľ je Peter. AWKWARD

I think not awkward when the practical meaning is "his name is Peter".

Other foreros may feel differently.

Perhaps not even (or at least not very differently), if also a certain context is given.

 

[morior_invictus]

I think not awkward when the practical meaning is "his name is Peter".

Actually, I thought about it a tad and I found one instance where it can be used without sounding awkward (I guess that is what you meant as well):

(na hodine veštenia)
A: Moje vnútorné oko mi hovorí, že každý kto sa volá Peter dnes zazrie morskú pannu.
B: Neverím! Môj priateľ je Peter! / Môj priateľ sa volá Peter! Hneď mu idem zavolať aby upínal zrak na všetko čo sa bude hýbať v akomkoľvek priestore naplnenom vodou a javiť ako postava bez šiat.
A: Hovorili ste niečo, Jaromil?
B: Aaale nič, pani veštiteľka. Ja len, že máte dnes vynikajúci habit na sebe.
A: Erm... vlastne som sa zabudla prezliecť z pyžama.
B, C, D, E, . . .:

(na diskotéke)
A: Bože, ako môže niekto dať svojmu dieťaťu meno Peter? Však je to otrasné meno.
B: No prepáč?! Môj priateľ je Peter! A mne sa to meno páči.

Perhaps not even (or at least not very differently), if also a certain context is given.

That is true, as well. Context is crucial but you will find lots of foreros here who just don't supply it so you have, basically, three options: (i) try to answer the question as best as you can (that's what I did when you gave us sentences with no context ), (ii) ask for context that may very well never be supplied, (iii) not answer the question posed.

 

[Londyncan69]

But it is the same grammatical construction – in line with this thread, it can also theoretically be "... je prevažne ženským športom." Or you could change the word order to mirror that of the phrase in question: "prevažne ženským športom je netball". The way to tell the subject in somewhat unclear cases like this one is to simply change the verb to one with different case agreement – it's the predicate that will have to change its case. In our example, you don't even have to change the verb.

Interesting. I am struggling to imagine a situation in which you might say “ženský šport je netballom”, just as you suggested I would. The closest I can get is to think of a school in which boys and girls play different sports. Boys play football. Girls have been playing Lacrosse. But this year, things have just changed and now girls will play Netball instead. It's a contrived example and if it feels wrong to say “ženský šport je netballom”, it would seem that netball is obviously the subject in the original sentence.

But how about the English sentence “John is Jane”. Let's imagine a man who sometimes pretends to be a woman. Some people know him as John. Some people know him as Jane. One day someone finds out that John and Jane are actually the same human being, and says: “John is Jane”. In English, John could be inferred to be the subject of the sentence by virtue of typical word order patterns, even if a poet might vary this typical word order pattern for aesthetic effect. After all “John is Jane” in this context isn't intended to be poetry. It's an expression of shock.

But let's take a Slovak variant of the story in which the same person is known by some people as Pavol and by others as Zuzana. And the person who discovers his deception says: “Pavol je Zuzana”. Is there anything to say what is the subject and what the predicate in “Pavol je Zuzana”, given the flexibility of word order in Slavic languages? I'm guessing the example is generalisable in some way to cases in which a speaker has to choose between nominative and instrumental. I'm searching for the exceptional case here but wonder if this isn't it.

Leaving thought experiments aside for a moment, since as a non-native speaker I'm probably getting them wrong, I've been indulging in the guilty pleasure of reading Slovak news websites again during a few spare moments, and I've collected a bit more real-world data.

So, today, I found:

(1) Havária v Černobyľskej jadrovej elektrárni v roku 1986 bola najväčšou podobnou katastrofou v ľudských dejinách, zasiahla veľkú časť Európy. Source: TA3.com

When I look for other treatments of the Chernobyl accident, I also find the instrumental e.g.:

(2) Černobyľská havária bola ojedinelou udalosťou, ťažko porovnateľnou s inou. Source: sk.wikipedia.org

But what is going on with these examples?

(3) Havária bola nakoniec klasifikovaná ako najvážnejšia hodnotením 7 na medzinárodnej stupnici (INES), čo je rovnaké hodnotenie ako mal Černobyľ. Source: sites.google.com/site/fukusimaenviro/

(4) Autobus vo Švédsku skončil v priekope, havária bola fatálna. Source: webnoviny.sk

(5) FAKTY X: Bola ropná havária v Mexickom zálive naplánovaná? Source: magazin.atlas.sk/

(6) Havária lietadla Malaysia Airlines bola nehoda. Source: www.sme.sk

(7) F1: Hovorca okruhu v Suzuke tvrdí: "Bianchiho havária bola nešťastná náhoda". Source: www.sport7.sk

(8) Havária malajzijského lietadla bola nehoda, rodiny odškodnia. Source: tvoravia.sk

The permanency/contingency distinction is well-established. See Morfológia slovenského jazyka above, and its similarity with other Slavic languages can be seen in English-languages sources (see Steven J. Clancy and Leon Strassen above).

So, there are a few hypotheses one can make.

H1. Some writers are making a linguistic mistake. The permanency/contingency distinction is well-established in spisovná slovenčina and some people are just using the language wrong.

H2. Some writers are making a perceptual mistake. They grasp the permanent/temporary distinction and their use of the nominative/instrumental case is a correct expression of their perception that the attribute they are describing is permanent/temporary. But they've either mistaken a permanent for a temporary attribute or vice versa.

H3. The question of whether an attribute is permanent or temporary borders on the philosophical in many cases. It can reasonably be argued either way and so it's no wonder that there is some confusion.

I am not sure that H2 and H3 entirely explain the differences between examples 1-2 and examples 3-8 but I have some sympathy for these explanations. But that's guesswork by a non-native speaker with a very limited grasp of the language.

 

[Concise]

Chapeau! To everyone who were involved in this discussion, but mainly to Londyncan69 for the well-structured question and its highly detailed nature.

I just got to the lesson in my course book which introduces “7. pád - inštrumentál”, but the text in my book flooded me with lots of examples of instrumental case, which go much beyond the basic understanding/usage and the grammatical explanation of this lesson lists 4 items of use.



So I am very happy that I found this thread, and although I need more time to fully grasp its content, I think that the complexity of the proper use of instrumental is Slovak is a sort of punishment for the simplicity of how to form it.

Which seems to be the easiest among all the cases (no “two-optioned game” like in genitive masculine, “g, h, ch, k” rule for masculine and neuter does not have an impact on this case, not even the foreign words have special forms in instrumental etc.)

So having translated and read multiplied times the excerpt quoted from http://www.juls.savba.sk/ediela/msj/msj-hq.pdf I dont understand some of the ‘sentences’ of the court of justice.

It is said about “Riaditeľ je mojim otcom.Môj priateľ je Petrom. ”

as an explanation that

These, I (non-native) think, are absolutely impossible by the criterion of the "temporary versus permanent characteristic" or "intrinsic/non-intrinsic" or "defining/non-defining" - justify it in whichever way you choose - trvalý, podstatný príznak as described in #4 - thank you MI!

My father is the permanent, intrinsic and invariable characteristic. There's no way that being a driver can be more intrinsic to who that person is than him being my father.
Same with Peter. He is Peter permanently. That is an intrinsic and unalterable part of who he is. The characteristic of being my friend is impermanent, temporary, non-intrinsic to Peter. It doesn't define him as a person.

and the logics behind was confirmed using another example:

Riaditeľ je môj otec.
Riaditeľ je mojim otcom. ERM... NOT GOOD

So far it was easily understandable.

So I thought the same situation is with Otto, because Archduke Otto was a son of somebody from the first day of his own life and remained the son of the same person until its own death.

So why “synom” was approved and why “syn” was rejected in the example raised by Londyncan69? See:

Arcivojvoda Otto bol synom posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.
Arcivojvoda Otto bol syn posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.

It could not be a simple typo, because the judgement was the same regarding another example:

Otto Habsburg-Lothringen bol najstarší syn cisára Karola I. a bývalý korunný princ Rakúsko-uhorskej monarchie. NOT OK
Otto Habsburg-Lothringen bol najstarším synom cisára Karola I. a bývalým korunným princom Rakúsko-uhorskej monarchie. OK

I am confused….

 

[Enquiring Mind]

A noun predicate after the copula may be nominative or instrumental; the nominative dominates in the expression of general or permanent qualities: byt Slovak 'be a Slovak', while the instrumental is strongly preferred in more concrete, topical, relativized contexts and hence commonly expresses professions, titles and functions: byt dóstojnikom/kniezatom/ svedkom 'be an officer/prince/witness'; blood and social relationships: byt dcerou/vdovcom/cudzincom 'be daughter/widower (of someone)/a foreigner'; various qualities expressed as nouns: bytpatolizačom/silakom 'be a sycophant/strongman', in which case the attribute may be expressed adjectivally with a generic noun: byt dobrym človekom/vazenym občanom 'be a good man/respected citizen'. (Slovak, David Short, p571)

The noun predicate after the copula may be in the nominative or the instrumental, but it's not an entirely free choice. We need to look not just at "permanent" qualities of nouns in isolation, but at the relativised use of the noun predicate in each individual context.

 

[Concise]

Thanks for your efforts to make me understand it, but I am not sure that I can see the difference between the sentences you reviewed and judged.

Do you mean that even if the “syn …..” in the sentence of

Arcivojvoda Otto bol synom posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.
Arcivojvoda Otto bol syn posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej.

is a permanent quality of “Otto”, but due to the “blood and social relationships” rule it as a predicate has to be in instrumental form?

And “Riaditeľ je mojim otcom” is incorrect, because even if one could seemingly apply the “professions, titles and functions” rule, but he cannot.

Why? Because my father can have indeed a profession/title/function eg. can be a director, so “Môj otec je riaditeľom.” would be correct, but when we mention that the position of a director is filled by my father, we do not link neither two entities by their “blood and social relationships”, nor we do not add any (second) title/profession/function to the director as an entity/subject????

Is my interpretation correct?

Btw “Vy ste svetovou senzáciou!”

 

[morior_invictus]

I think you might be overanalyzing it. In the text that I quoted in #4, the author noted that "obsahový/prísudkový nominatív" (as opposed to "prísudkový inštrumentál") is especially used in definitions, when identifying subjects etc. and that is how "Arcivojvoda Otto bol syn posledného rakúskeho cisára a uhorského kráľa, Karola I., a jeho manželky Zity Bourbonsko-Parmskej." sounds to me - as something you might find in a dictionary entry under Arcivojvoda Otto ("Arcivojvoda Otto bol X" where X = "syn posledného. . . "). Does it mean that you would only find such sentence structures in dictionaries? No. You might also find them in various academic papers but also come across people who are simply fond of using the nominative case where others would use the instrumental one. Would such people be on the grammar police's radar? Nothing seems to suggest that the use of the nominative case would be grammatically incorrect (hence the words "dominates" / "strongly preferred" etc. in the text EM quoted above) so the answer is very likely "no" but to many people such structures might sound stilted or dictionary-like.

Similarly to "Arcivojvoda Otto bol syn. . .", "Môj otec je riaditeľ." sounds to me like you are simply telling the listener what your father's job title is rather than telling them what your father does for a living, if that makes any sense. Trying to be more concrete in one's answer (or to place the predicate within a certain time frame) would prompt many people to use the instrumental case (i.e. ". . .riaditeľom školy" rather than ". . . riaditeľ školy" - again, I'm sure you would also come across people who would use the latter instead).

"Riaditeľ je môj otec." / "Riaditeľ je mojim otcom." (these two have either a slightly unnatural word order - if "riaditeľ" functions as the predicate and "môj otec" as the subject - or there would need to be some context in which one would feel the need to qualify "riaditeľ" with "môj otec" rather than the other way around - perhaps, if one just found out that the (school) principal is their (biological) father?).

Last but not least, it may be worth mentioning for learners (as I see that I did not touch on that subject in 2015) that in my neck of the woods, no man would refer to his male friend as "priateľ" unless he would want others to think that he's very fond of other men. This may or may not be also indicative of other parts of the country.