1 Introduction

Numeral constructions and light-headed relatives (LHRs) in Bosnian/Croatian/Serbian (BCS) reveal a tension between representations of case syncretism and representations of case priority. Caha (2009) demonstrates that syncretism is possible only among adjacent cases ordered in a universal sequence and that this pattern can be captured through a hierarchical decomposition of case. Given the universality of the analysis, the syncretism patterns are applicable to BCS, as Caha indeed shows. However, the case interactions within both BCS numeral and relative constructions—with additional support from German—conflict with the hierarchy predicted by Caha’s case sequence.¹ In particular, these examples indicate that the lexical cases (genitive, locative, dative, instrumental) clash with one another, and none can take priority over the others. By contrast, Caha’s decomposition predicts that instrumental overrides dative, which overrides locative, which in turn overrides genitive. To resolve this paradox, this paper proposes that the case system should be layered to accommodate both representations: priority is determined through containment relations of syntactic set structures, while syncretism is analyzed post-syntactically after ‘flattening’ of the structures through a unification operation (see Ackema & Neeleman 2018). The following discussion reveals the conflict through examinations of both syncretism and priority in the relevant examples and then introduces the two-level solution.

2 Representations of syncretism

Caha (2009) formalizes the universal patterns of case syncretism as Universal Contiguity:

With reference to BCS, Caha adds the “prepositional” (locative) case to the sequence between genitive and dative, noting that it is largely syncretic with dative apart from minor differences in stress.² While this may signal that locative is moving toward elimination from BCS, the data presented in the following sections indicate that locative does contribute to the priority paradigm and should be included in the current analysis.³ Caha contends that a hierarchy of features based on the cumulative decomposition of case is necessary to capture the adjacency constraint on syncretism (see also Caha 2019b). This hierarchy can be adapted to the layout in (2), where each case set is built with the addition of a single identifying feature. At this point, it is worth mentioning that some analyses of case syncretism disagree with the organization of this hierarchy (e.g. Harðarson 2016; Graf 2019; Zompì 2019; Bárány 2021), suggesting that the feature decomposition may not be as incremental as Caha (2009) proposes. For now, I assume that Caha’s decomposition is correct, but §4 reflects on how the two-level account proposed in this paper is compatible with these alternate views of syncretism, as well as with languages in which both the priority and syncretism patterns align with (2). I emphasize that the decomposition in (2) integrates the general patterns of syncretism for the relevant BCS cases without assuming Caha’s nanosyntactic underpinnings.

In line with this decomposition, Table 1 shows the syncretisms found in the declension of prijatelj ‘friend’ (for the complete BCS nominal paradigm see Caha 2009: 238–239).

In Caha’s analysis, the spell-out of syncretic forms is governed by the Superset Principle, where the inserted form contains (i.e. is a minimal superset of) the set of case features on the node. Alternatively, some analyses of syncretism utilize underspecification, where the inserted form is a maximal subset of the necessary case features. Impoverishment also seems to be a valid option: deletion of the outermost feature of each successive case set in (2) would reduce that set to the features of the one before it. For the most part, the data in this paper do not bear on which method to use, but §4 contains some speculation regarding the use of impoverishment.

3 Representations of priority

In addition to syncretism, case hierarchies are commonly used to address priority patterns (Vogel 2001). This section reviews the behavior of case in both BCS numeral constructions as well as BCS and German relative constructions, which each produce the decomposition in (3) (see Assmann 2013; Himmelreich 2017 for similar systems). If priority is based on containment so that a case C₁ can override another case C₂ if C₂ is a subset of C₁, (3) predicts the following sequence of priority: nominative < accusative < lexical (compare Pittner 1995; Grimm 2007; Zompì 2019; Bárány 2021). As the examples will show, the lexical cases can override accusative, which in turn overrides nominative, but the lexical cases appear to ‘clash’ amongst themselves by hypothesis due to a lack of containment.

Turning first to BCS higher numeral constructions (containing ‘five’ and above), priority is particularly noticeable in the interactions of genitive with the other cases, as it is widely accepted that numerals impose genitive case on their complements (see e.g. Franks 1995; Wechsler & Zlatić 2003; Bošković 2006). Numeral constructions are grammatical across nominative, accusative, and genitive environments, exemplified in (4) with an accusative environment (Giusti & Leko 1995; Zlatić 1997; Wechsler & Zlatić 2003).

On the other hand, numeral constructions are largely considered ungrammatical as complements of dative- and instrumental-case-assigning verbs, exemplified in (5) with the dative-assigning verb pomoći (Franks 2002; Bošković 2006; 2008; Stjepanović 2012). I put locative case aside for now—locative only surfaces on complements of prepositions in BCS, but numeral constructions behave differently with prepositions than they do as complements of lexical-case-assigning verbs (Zlatić 1997; Wechsler & Zlatić 2003; Bošković 2006; 2008).

Notice that in (5), the result is ungrammatical whether the nominal form is genitive or dative (similarly with instrumental). The overall distribution of numeral constructions thus suggests that genitive can override nominative and accusative but clashes with both dative and instrumental.

As it happens, the BCS LHRs discussed below provide independent evidence of the same clashes (see Citko 2004). The crucial evidence for case priority comes from the examples in which the light head is omitted. We will see that a genitive head cannot be omitted when the wh-pronoun is either dative or instrumental (and vice versa), indicating a clash between these cases. By contrast, a nominative head is always optional, and an accusative head is optional with a wh-pronoun realizing any of the lexical cases. This possibility of omitting the head suggests that the case of the wh-pronoun is allowed to take precedence, again predicting the sequence nominative < accusative < lexical.

We now turn to a case-by-case discussion of the paradigm. Given the contrived nature of these examples, there is some variability in judgments, which is discussed in the footnotes to avoid complication. Beginning with (6), the matrix clause is nominative, while the relative clause is manipulated to assess the six case combinations. Here, the light head ono is always optional.⁴ Since nominative is not required to surface in the construction via the head, it appears that all cases can take priority over nominative. This is because without the head, the case of the relative clause surfaces on the relative pronoun, while the nominative case of the matrix clause is not realized.

The accusative examples in (7) reflect a similar pattern: accusative is overridden by the lexical cases, indicated by the optionality of the head in (7c–f). The head can also be omitted in (7b) when both clauses realize accusative. In (7a), however, the head is required, suggesting that nominative cannot override accusative despite the fact that što is a nominative/accusative syncretic form. The conflict in (7a) that would result from omitting the head crucially differs from the behavior of BCS free relatives (FRs), which allow repair by syncretism (Milićević 2011). This fundamental contrast may be attributed to a difference in syntactic structure (see Citko 2004 for a related discussion of Polish).⁵

In the genitive examples, the head is optional only when both the matrix and relative clauses are genitive. This further substantiates the claim that genitive takes priority over nominative and accusative but not vice versa, since nominative and accusative wh-pronouns cannot appear without the head (8a–b).⁶ Similarly, the inability of locative, dative, and instrumental wh-pronouns to occur without the head in (8d–f) indicates that the lexical cases cannot take priority over genitive.

The same is true for the remaining locative, dative, and instrumental examples in the appendix (with additional comments): the head is optional only with case matching between clauses. When nominative or accusative occurs on the wh-pronoun, or when any two lexical cases are paired, the head cannot be omitted. Altogether, these LHRs demonstrate a sequence of case priority where nominative is overridden by accusative which is overridden by the lexical cases. Moreover, the interaction of genitive with the other cases exactly parallels the numeral constructions.

Remarkably, German FRs provide a non-Slavic parallel of the BCS LHRs, though without instrumental case since German does not distinguish it morphologically. While some speakers adhere to strict case matching in FRs (Vogel 2001; Vogel & Frisch 2003), others display the pattern in (9) where a more complex case in the relative clause can override the matrix case. The most relevant examples are presented, but the full paradigm can be found in Himmelreich 2017: 57–59.

As with BCS, the case of the pronoun in (9a–b) reveals that nominative is overridden by accusative, which is overridden by genitive. The ungrammaticality of (9c–d) indicates a clash between genitive and dative, as neither form of the wh-pronoun is grammatical.⁷ Since the priority pattern is not restricted to either BCS or numeral constructions, these examples suggest that case priority is indeed prevalent and should be considered alongside patterns of syncretism. Moreover, Caha (2009) shows that German syncretism patterns conform to Universal Contiguity; thus, German, like BCS, displays a priority/syncretism paradox.

The containment relations between the cases in (3) easily capture the observed patterns of priority.⁸ These feature sets allow all cases to override nominative, since it is contained in all sets. Genitive, locative, dative, and instrumental also override accusative, since all contain the set of accusative features. However, the individual sets of genitive, locative, dative, and instrumental are predicted to clash with each other, as none of them fully contain the features of the others. Crucially, this lack of containment among the lexical cases differs from the syncretism configuration given in (2). Using the system in (3), there is no obvious way to capture Universal Contiguity. Take the paradigm in Table 1 for example: the apparent dative/instrumental syncretism cannot be analyzed here using supersets, subsets, or impoverishment, since neither set contains the other. On the other hand, the system in (2) does not capture the priority patterns observed in the numeral and relative constructions, as both dative and instrumental are predicted to override genitive. This fundamental conflict between priority and syncretism suggests that the two patterns may require different analyses, though the distribution of case features should ideally remain constant throughout.

4 A possible solution: Two levels of representation

While the feature sets in (2) address syncretism, they fail to predict the priority patterns captured by the sets in (3). However, the use of two distinct sets of case features within a single language does not contribute to a contentful theory. Instead, (10) shows that it may be possible to derive the general shape of the priority relations in (3) from the features of (2). The structural cases (nominative and accusative) remain sets of atomic features as we saw in (2) and (3); the lexical cases (genitive, locative, dative, and instrumental) contain an embedded set in addition to the nom and acc features. This decomposition provides a basis for the case clashes.

Rather than considering all cases as sets of atomic features as in (2), (10) suggests that the priority relations can be derived through a decomposition into features and embedded sets. In both (10) and (3), nominative is composed of one element, accusative of two, and genitive, locative, dative, and instrumental of three elements.⁹ If we maintain that a case C₁ overrides another C₂ when C₁ is composed of all elements of C₂, then (10) correctly captures the observed patterns of case priority. For example, dative overrides accusative since it includes the nom and acc features that define accusative. However, dative clashes with genitive due to a lack of containment. Genitive is composed of the features nom, acc, and gen, but dative does not contain gen as an atomic feature, only as a member of the embedded set {gen, loc, dat}.

The conflict between priority and syncretism can then be resolved if priority relations are determined by set relations in the syntax. These set structures are post-syntactically ‘flattened’ to the sets of features in (2), after which spell-out takes place and potentially leads to syncretism.¹⁰ Flattening amounts to a unification of the outermost and embedded sets through removal of internal structure; as such, is not a difficult assumption to make because no complex mechanisms are added to the grammar. Information is simply removed, but the content of each case remains constant throughout.

Let us consider how this unfolds in the BCS examples. We have seen that a case clash occurs when the head is omitted in examples such as (8d), where the head realizes genitive and the wh-pronoun realizes locative. This outcome can be illustrated with the structure below, which loosely follows Citko’s (2004) analysis of LHRs. Priority is determined through containment relations in the syntax. In (11), the features of the head are not recoverable from the features of the wh-pronoun because there is no containment between the genitive and locative cases at this level. Both cases include the nom and acc features, but they differ with regard to gen. In the composition of genitive, gen is an atomic feature, while in locative it only appears as a member of the embedded set {gen, loc}. Since the composition of genitive is not fully contained within the composition of locative, the features of head are not recoverable, and it cannot be grammatically omitted.

Syncretism can be derived as a post-syntactic by-product after flattening the internal set structure to yield sets of features. As discussed regarding (7a), syncretism does not appear to affect the BCS LHRs, but it has been observed that syncretism resolves feature conflicts in certain constructions (Milićević 2011; Himmelreich 2017; Bergsma 2019). Continuing with the example from above, let us consider how a hypothetical repair would work. After flattening, the set of locative features on the wh-pronoun contains the genitive features of the head, as depicted in (12). Therefore, operations on the larger set of features containing loc can produce {nom, acc, gen}.

Thus far, it has not been necessary to know precisely which method is used to analyze syncretism, the critical point being that the flattened sets are related through containment. However, it now seems that impoverishment may best accommodate this repair potential in the two-level system, at least for a subset of the examples. This is because impoverishment can be precisely formulated to address idiosyncrasies, and constructions that do not exhibit repair potential simply lack the necessary deletions. If the clash in (11) were repairable through syncretism, one could imagine a rule such as (13) that reduces the flattened set of locative features to genitive in a specific context, such as on the wh-pronoun in the environment of a genitive light head.¹¹ It would then be possible to omit the head since its features match those of the wh-pronoun. Note that in order to derive the correct syncretism predictions, impoverishment must be restricted to the outermost feature of a case set, perhaps through a requirement on the well-formedness of case sets with respect to (2). Zompì (2019) proposes a similar constraint using Graduality.

This repair is not observed in BCS LHRs, so the rule in (13) is merely hypothetical. Flattening does occur in the derivation, but case override is restricted to the syntax, so the priority relations stand as they did in (11). This shows that cases may clash, but at the level of spell-out, they form unified sets that can be manipulated to derive a syncretic form if the relevant rules exist.

For certain repairs, it is conceivable that impoverishment would have to occur prior to flattening to repair the mismatch at the correct case level. Though impoverishment is typically considered a morphological operation, Keine (2010) argues for the possibility of syntactic impoverishment. Given Zompì’s (2019) Graduality, it seems that impoverishment of the embedded sets would only be able to reduce the case sets in (10) to nominative or accusative. More research would be required to work this out in detail, and whether this solution is feasible in the constructions where this repair is observed is a matter of further analysis. However, early impoverishment does appear appropriate for certain patterns. For example, Bárány (2021) examines Spanish differential object marking, where dative is syncretic with accusative to the exclusion of genitive. At first glance, such early impoverishment seems applicable to the syncretism patterns of languages that do not conform to Caha’s (2009) Universal Contiguity.

Up to this point, I have assumed that Caha’s (2009) view of case-feature accumulation is correct for syncretism; sets of case features grow incrementally with the addition of a single feature. In examining exceptions to Universal Contiguity, other analyses of syncretism implement less exacting ideas of feature growth, positing that the lexical cases are not strictly ordered with respect to each other (e.g. Harðarson 2016; Graf 2019; Zompì 2019; Bárány 2021). These analyses differ slightly in their implementations, but their proposals somewhat resemble my priority hierarchy. Bárány (2021) and Graf (2019) both argue for partially ordered case hierarchies to maintain the general principle of contiguity but allow for more flexibility. Their predictions align with Zompì’s (2019) case-class hierarchy, where the cases within each class are unordered with respect to each other; this amounts to a containment hierarchy of unmarked ⊂ marked ⊂ oblique, where genitive is not a member of any class. Harðarson (2016) suggests a weaker form of contiguity but develops language-specific case hierarchies. Overall, the two-level system proposed here does seem amenable to these alternative views of syncretism if cases are represented syntactically as sets of structures. Without this level distinction, it is difficult to determine how a single language can contain a priority/syncretism paradox where the cases that clash with each other are syncretic in other environments; here, the above analyses fall short. They are perhaps sufficient to address the priority data for BCS and German, but a more articulated hierarchy for the lexical cases is necessary to accurately capture the syncretism data. Assuming that all languages have two levels of case, then the proposal advanced in this paper has the flexibility to accommodate additional patterns if we allow the timing of flattening to vary cross-linguistically. For example, in the languages discussed by the above sources, it is possible that flattening occurs later than it does in BCS and German so that syncretism operates on the basis of unflattened set structures. Alternatively, these languages may have only the unflattened level of case.

On the other hand, there are also languages in which the priority patterns appear to align with the predictions made by the Universal Contiguity hierarchy. This is the focus of Caha’s (2019a) work on case competition, in which he principally investigates Russian and Ossetic. In Russian numeral constructions, for example, the numeral assigns genitive case to its complement, as we saw earlier with BCS. This genitive surfaces in nominative and accusative case environments but, in contrast to BCS, is overridden in the lexical case environments. Caha cites the following examples:

This predicts that the lexical cases override genitive, which overrides nominative and accusative, roughly corresponding to the hierarchy predicted by Universal Contiguity. The priority data alone are not sufficient to determine the precise order of all lexical cases with respect to each other, but in Caha’s investigation, there is no strong evidence to suggest that the syncretism and priority hierarchies vary within a single language. Again, it is possible that the behavior of these languages could be accommodated in the current system by adjusting the timing of the flattening operation. Since priority relations are determined in the syntax, languages such as Russian could have flattening early in the derivation so that priority is determined on the basis of the flattened case sets. Otherwise, these languages may contain only the flattened level of case. I leave it to future research to determine the exact implementation that would be required to address this typological variation within the system proposed here.

5 Conclusion

This paper highlights a conflict between representations of case syncretism and case priority through an examination of numeral constructions and relative constructions in BCS, with added support from German. The conflict is resolved by introducing two levels of case representation, where the syntactic interactions of set structures define priority relations and post-syntactic flattening yields sets of case features that determine syncretism. Such a solution predicts that case syncretism cannot be analyzed with a purely syntactic account—at least in languages containing this priority/syncretism paradox—with implications for syncretism more generally. The solution seems to be incompatible with the nanosyntactic view of syncretism in Caha 2009 where each case is a projecting head, but further research is required in this area.

Abbreviations

3 = third person, acc = accusative, aux = auxiliary, dat = dative, f = feminine, gen = genitive, instr = instrumental, loc = locative, nom = nominative, pl = plural, pst = past, refl = reflexive, sg = singular

Competing interests

The author has no competing interests to declare.