Reference and Modification in U niversal D ependencies (2025)

Abstract: Is the framework of Universal Dependencies (UD) compatible with findings from linguistic typology? To address this question, we need to systematically review how UD represents linguistic constructions in the world’s languages, and how it handles the range of morphosyntactic variation attested in linguistic typology. In this paper, we start this review by discussing reference and modification constructions. The review shows that, although UD can represent all major constructions in this area, there are a number of cases where UD categories do not align systematically with a typological classification of constructions, and where constructional similarity is therefore not transparent across languages. We also identify limitations in the representation of certain morphosyntactic strategies, notably indexation and linkers. To overcome these limitations, we propose a number of revisions that may be considered for future versions of UD.

## introduction universal dependencies (ud) is a framework for morphosyntactic annotation, which is designed to be applicable to all human languages in a way that enables meaningful cross-linguistic comparisons @xcite @xcite . to find out whether ud meets these requirements, @xcite proposes to build a constructicon for ud based on the survey of universal constructions and morphosyntactic realization strategies in @xcite and the mocca database of comparative concepts derived from it @xcite . in this framework, constructions are formfunction pairings defined solely in terms of their function (hence universal), while strategies are defined by the pairing of a function with some crosslinguistically identifiable morphosyntactic form. if we can provide a ud analysis for every combination of a construction and a strategy, then we can assess to what extent ud systematically captures cross-linguistic similarities and differences. in the same process, we can also gather evidence of gaps or inconsistencies in the current ud guidelines, and propose improvements for future versions. 1 in this paper, we present a first contribution to this project by discussing one of the most central constructions in the world's languages, that of nominal phrases, or referring expressions, including modification constructions that provide additional information about referents via their properties, their quantities, or their relations to other objects. reference and modification constructions are discussed in chapters 3-5 of @xcite . ## reference constructions referring phrases are used to pick out and identify a referent, and they can be classified semantically into three broad categories, illustrated with a russian example in (1) @xcite : ver-e i gave book-acc vera-dat 'i gave vera the book' while ja identifies its referent contextually as the individual fulfilling the speaker role, knigu identifies the referent as belonging to a certain type (the book type), and vere refers to a unique individual. given these three semantic categories, we can define three basic reference constructions: pronouns, with contextual reference; nouns, with type reference; and proper nouns, with individual reference. the basic reference constructions can be further subdivided both with respect to semantic content and information packaging. on the semantic side, nouns are often subdivided according to (degrees of) animacy, and pronoun systems often reflect ontological categories like person, thing, place, time and manner @xcite . on the information packaging side, the most important notion is information status, which concerns the identifiability and accessibility of a referent. information status is really a continuum, ranging from referents already mentioned in the discourse to purely hypothetical ones, but a broad distinction can be made between definite and indefinite referring expressions, where the defining criterion of the former is that the referent is already known to both speaker and hearer @xcite . the basic constructions are commonly realized on their own, as in (1), but especially (common) nouns are often combined with other expressions to form complex referring phrases. this often involves modification constructions, which will be discussed in section 3, but it is also common to combine basic reference constructions. for example, contextual reference and type reference are often combined, as in the phrase this book, where the demonstrative this is used to constrain the type reference of the noun book. this combined use of the demonstrative -as opposed to its use as a pronoun on its own -is a subtype of the determiner construction, which also includes articles. determiners are generally used to indicate the information status of the referent. however, while articles only express information status, demonstratives in addition encodes location with respect to the speaker and hearer @xcite . besides determiner constructions, it is common to combine several proper nouns, as in susan smith, and to combine common and proper nouns, as in aunt susan. more complex nominal phrases can be formed via modification, as discussed below in section 3. when it comes to morphosyntactic strategies, pronouns, nouns and proper nouns are most commonly realized as single words, but pronouns can also appear in reduced forms in many languages. they may be realized as clitics, that is, as morphemes that have the syntactic characteristics of a word but depend phonologically on another word or phrase; they may appear as affixes on the predicate, a strategy known as indexation; or they may not be phonetically realized at all, a zero strategy. determiners can be realized as affixes on the noun or as separate words (sometimes with indexation of noun features such as number and gender). in general, strategies for referring expressions can be ranked on an accessibility scale @xcite @xcite , where shorter expressions are preferred for higher accessibility referents. how are the basic reference constructions represented in ud? ## modification constructions the information packaging function of modifiers, or attributive phrases, is to add information to help identify the referent of a referring phrase. croft (2022) distinguishes six basic modification constructions, exemplified in (2): in (2a), black is an adjectival modifier, or simply adjective in croft's terminology, which helps identify the referent of the head noun dog by adding information about a property, in this case its color. besides color, adjectival modifiers commonly denote properties such as shape (round), age (old), value (good), and dimension (big) @xcite . from an information packaging point of view, adjectival modifiers are said to be subcategorizing. adjectival modifiers can be combined with admodifiers, like very in a very big house, which describe semantic operations on the scale denoted by the modifier. besides intensifiers like very, admodifiers can be downtoners (a rather big house), comparatives (a bigger house), or superlatives (the biggest house). the following three examples (2b-2d) instead belong to the class of selecting modifiers, whose information packaging function is to select an instance or set of instances using information about quantity or set membership. this is a diverse class, where three main constructions are distinguished: numeral quantifiers, set-member terms, and mensural terms @xcite . numeral quantifiers include cardinal numerals like five in (2b) together with a wide range of different quantifiers like several (a vague numeral), most (a proportional quantifier), and each (a distributive quantifier). set-member terms include ordinal numerals like third in (2c) as well as non-numerical terms like next, last, and other. numeral quantifiers and set-member terms both presuppose that the head noun denotes an individuated entity. this is not the case for mensural terms, exemplified by the measure term a pound of in (2d) and including a diverse set of constructions referring to containers (cup), groups (flock) or pieces (slice), among others @xcite . the next modification construction, exemplified in (2e), is nominal modification, where the referent of the head noun is identified by its relation to another referent, such as the kinship relation in peter's mother. the number of relations that can be invoked in this way is in principle unlimited, but other common relations are ownership (peter's car), body-part relations (peter's arm), and figureground relations (the book on the table) @xcite . from an information packaging point of view, nominal modifiers have a situating function, which makes them semantically similar to the pronoun and determiner constructions discussed in section 2. construction strategy ud annotation adjectival modifier simple/indexation re amod -→ adj[features] admodifier word adj advmod -→ adv affix adj[@xmath0: adposition nom nmod -→ re case -→ adp nominal modifier simple/indexation re nmod -→ nom[features] re det -→ nom[features] flag: affix re nmod -→ nom[@xmath1: adposition re nmod -→ nom case -→ adp compounding re compound -→ nom the final example in (2f) shows action modification, where the referent is being identified in relation to an event, and its prototypical realization in the form of a relative clause. since subordinate clauses will be the topic of a later paper, we will not discuss action modification further in this paper, except to note that the relative clause construction can sometimes be recruited for property modification as an alternative to adjectival modification @xcite . 6 the morphosyntactic strategies of modification constructions can be divided into four main types croft (2022, pp. 114-138): as discussed above, modifiers can furthermore be accompanied by admodifiers, which can be realized as independent words or affixes. how does ud represent the different modification constructions and strategies? in ## discussion while our review has shown that the ud annotation framework can represent all the major constructions and strategies for reference and modification discussed in croft (2022), we have also seen that the correspondence between comparative concepts and elements of the ud annotation is quite complex. of course, ud has developed without an explicit aim to represent constructions, let alone distinguish strategies for those constructions across languages. nevertheless, our review reveals ways in which ud can capture properties of constructions and strategies, using a combination of syntactic relations and part-of-speech tags. first, some, perhaps most, of the syntactic relations closely match the major information packaging constructions described in croft (2022), albeit subdivided. for the constructions reviewed here, the main information packaging constructions are modification and admodification. our suggestions for future revisions of the relations, specifically distinguishing admod from advmod and having a single mod relation replacing det, amod and nummod, increases this parallelism. naturally, there will be some mismatches between construction function and morphosyntactic form, but we assume that these are relatively infrequent compared to the general matching of form and function. another suggestion of ours that makes ud relations more closely match constructions is for a uniform representation of mensural constructions such that the measured noun is the head, which is facilitated by analyzing the etymological adposition in the pseudo-partitive strategy as a linker, not a flag. second, some of the part-of-speech categories are close to semantic categories. for example, num describes the semantic category of numerals; in fact, in many languages (most famously russian), different numerals use different modification constructions. the categories noun, propn and pron parallel the distinction between type reference, individual reference, and contextual reference. modification is characterized by a similar information packaging function carried out by different semantic categories of modifiers. our narrowing of det to articles and demonstratives, and introducing the new tag qnt, again increases this parallelism. third, ud must represent independent words that form part of certain strategies (also known as "function words"), since they are part of morphosyntax. this is currently done using syntactic relations, part-of-speech tags, or both. for a better treatment of modification, we suggest a new lnk relation, distinct from case, to handle the grammaticalized function word in the pseudo-partitive strategy for mensural constructions, as well as in certain genitive and other modification constructions. the linker itself is assigned the tag part, a tag that is used for function words in a variety of strategies. ## conclusion in this paper, we have taken a first step towards a constructicon for ud, in the sense of @xcite , by reviewing the way ud annotates constructions and strategies for reference and modification, following the taxonomy of @xcite . the constructicon is shown in tables 1 and 2 , where we outline how these constructions and strategies are currently annotated according to the ud guide-lines. (in passing, we have also remarked on a few inconsistencies in the way that these guidelines are applied across languages.) on the positive side, we have found that ud can represent almost all constructions and strategies discussed in the survey. on the negative side, we have found that ud categories do not always align systematically with comparative concepts from typology, that there is sometimes a conflict between annotating elements of constructions and strategies, respectively, and that some strategies are not well captured in the ud framework. in some cases, we have made concrete proposals for future revisions of ud, revisions that would improve the correspondence between ud categories and comparative concepts. it is worth clarifying that these revisions are incompatible with the current version of the ud guidelines (v2), since they involve changes to the set of syntactic relations and part-of-speech tags, which means that they could only be considered for v3 of the guidelines. moreover, these proposals need to be evaluated also from other perspectives, since ud is designed as "a very subtle compromise between a number of competing criteria" (de @xcite and should be suitable for language-specific analysis as well as typological language comparison, and should be accessible to non-experts and suitable for processing by computers. finally, the discussion needs to be informed by a more comprehensive review of the ud framework, covering all major types of constructions and strategies. it is our goal to continue this review in a series of future publications.