Computational Methods for the Analysis of Complementizer Variability in Language and Literature: The Case of H ebrew “she-” and “ki” (2024)

Abstract: We demonstrate a computational method for analyzing complementizer variability within language and literature, focusing on Hebrew as a test case. The primary complementizers in Hebrew are “she-” and “ki”. We first run a large-scale corpus analysis to determine the relative preference for one or the other of these complementizers given the preceding verb. On top of this foundation, we leverage clustering methods to measure the degree of interchangeability between the complementizers for each verb. The resulting tables, which provide this information for all common complement-taking verbs in Hebrew, are a first-of-its-kind lexical resource which we provide to the NLP community. Upon this foundation, we demonstrate a computational method to analyze literary works for unusual and unexpected complementizer usages deserving of literary analysis.

## introduction natural languages offer speakers a variety of means for expressing their sentiment and attitude toward events, be they actualized or unactualized. while the literature has traditionally focused on lexical items that convey sentiment and attitude (verbs, adjectives, nouns; underlined in (1)-( 2 )), it is well known that functional morphemes such as subordinating particles (complementizers; boldfaced in the examples) and mood inflection are also implicated in the expression of such meanings in certain languages @xcite . we {are proud / believe } that our athletes did their very best. recent work on the interaction between attitude predicates and the grammatical forms they "select" in the embedded clause has pointed to subtle semantic effects of choosing one complementizer over another (in greek; @xcite , or one inflected form over another (in romance languages; portner and rubinstein 2020; @xcite . in contemporary hebrew, the language we focus on in this paper, the variation between šeand ki as complementizers has not been recognized as relating to the grammar of embedding, and has often been attributed to register: ki is viewed as being more formal (see @xcite . 1 understanding patterns of clausal complementation in a language and the allowed range of variation is crucial for both comprehension and production. the distinctions are subtle and may seem arbitrary. they are known to present substantial difficulty even for advanced second language (l2) learners (e.g,. @xcite french; @xcite . this paper presents the first attempt we know of to explore aspects of complementizer distribution and use from a computational perspective, in hebrew but also more generally. as we survey in section 2, earlier computational studies of clausal embedding in attitude contexts have focused on english or on curated annotations. corpus-informed studies have been limited to languages with mood inflection (e.g., french; petkovic and rabiet 2016), leaving complementizer variability unexplored. the contributions of the present paper are as follows: ## related work large-scale datasets allowing for the investigation of clausal embedding have been developed within the megaattitude project. 2 in particular, the megaacceptability dataset (white and rawlins, 2020) provides acceptability judgments on the distribution of 1,000 attitude verbs in 50 syntactic frames in english. additional datasets explore inferences patterns associated with attitude verbs and their interaction with elements such as negation and tense @xcite . @xcite provide a database of theoretically informed syntactic and semantic properties of a set of 50 attitude verbs in 15 languages. the rich linguistic profile of each verb (including its complement types, factuality inferences, interaction with negation, focus sensitivity, gradability and more) is summarized in a table based on experts' judgments in response to a questionnaire. hebrew is included in this database, but information about complementizer variability is lacking from its description. moreover, the database provides information about a small set of verbs and is based on translation from english, not on language-internal distributions. computational resources for languages that have observable mood inflection in embedded environments include mood as a target of morphological annotation (e.g., the romance verbal inflection dataset by @xcite ; romance languages in @xcite . @xcite provide a corpusbased description of mood variation in embedded clauses in french. however, languages in which mood is marked on a subordinating particle have 2 http://megaattitude.io/ not yet received attention from a computational perspective. in the nlp literature on hebrew, @xcite provide a corpus-informed dictionary of about 3,000 verbs along with the number and type of complements they tend to occur with, including clauses. the two complementizers šeand ki were treated as interchangeable in this earlier work. our work extends this lexicon with detailed information about the complementizer variability characteristic of each verb. the question of whether authors of hebrew literature adhere to the same complementizer tendencies as found in other text types has not been previously explored. nevertheless, we note that in one study of embedded clauses in hebrew @xcite , examples of complementizer use from hebrew literature are cited alongside those of newspapers, without any differentiation between the corpora. ## enriched verbal lexicon previous literature noticed semantic trends in complementizer choice, but did not leave room for variation. for example, zuckermann (2006) suggests the existence of a class of desire ("liking") verbs which categorically disallow ki (pp. 81-82). our data shows that association with this complementizer in fact forms a scale among verbs that express desire and preference, with roce ('wants') on one end, meqave ('hopes') on the other end, and maqadif ('prefers') somewhere in between (1%-8%-16% occurrence with ki). similarly, our llm-based method uncovers more variation than is apparent from existing resources. an example is the verb megale, which zuckermann (2006, 87) translates as 'discovers' and classifies as unlikely to occur with ki. in our corpus, a substantial 36% of the verb's occurrence with an overt complementizer are in fact with ki. the cluster that is most strongly associated with this complementizer uncovers a second use of the verb, shown in (3). in this use the verb is associated with inanimate subjects and conveys the meaning of 'reveals'. ## complementizer propensities: visualization and analysis as described above, in order to visualize the differences in complementizer variability across different types of usages of a given complementtaking verb, we generate t-sne plots of the contextualized embeddings of the complementizers for a large set of sentences (up to 20k) for each verb. for example, in figure 2 , we plot 20,000 instances of complementizers which open a subordinate clause for the verb qala (in the qal conjugation; see ‫קל‬ ‫עלי‬ in to be sure, figure 2 contains far more blue than red, indicating that on the whole, this verb is generally used with the complementizer ki. however, red points are interspersed throughout the plot, indicating that the complementizer šeis also attested as a practical option for the same types of sentences; i.e., in almost all cases of complement clauses with the verb qala, the two complementiz-ers can be freely interchanged without worrying that the resulting sentence will sound odd or unnatural to present-day hebrew readers. however, there are two substantially-sized homogeneous sections on the plot, which indicate specific uses of one or the other of the complementizers. one such section is the red cluster at the bottom of the graph. inspection of the sentences represented by these points reveals that they all bear inflections of the idiomatic phrase ‫יעלה‬ ‫לא‬ ‫הדעת‬ ‫על‬ (lo yaqale qal ha-daqat 'it is inconceivable'; lit. 'it would not rise up upon the mind'). the implication, therefore, is that although this verb can generally be used with either complementizer, when it comes to its use within this idiomatic phrase, it is almost exclusively used with the complementizer še-. conversely, at the top right of the plot, we find a homogeneously blue section. inspection of these sentences reveals what appears to be a typographic concern: all of the sentences contain a specification of a percentage statistic immediately after the complementizer, written out in digits and a percent sign as in (4). for instance: in contrast, the plot for the verb hoxiax (figure 3 ) has no solid homogeneous clusters; rather, the red points are fairly evenly interspersed throughout the plot. this indicates that for this verb, both complementizers are accessible. even though the use of ki is somewhat more frequent with this verb, it can optionally be switched out for šewithout violating the expectations of native speakers. a reverse phenomenon emerges from the plot for the verb higid (figure 4 ), a suppletive form in the paradigm of 'said, told'. as opposed to the plot for qala, in which there were a few isolated homogeneous clusters, here the predominant majority of the plot is homogeneously red, reflecting the fact that this verb is used almost exclusively with the complementizer šewhen it embeds a clause; the complementizer ki is generally not a practical option. however, there are a number of areas in the plot where we find blue points interspersed among the red. inspection of these points reveals that they are sentences with a particular syntactic-semantic profile, exemplified in ( 5 ). in these cases, the impersonal nature of the sentence is correlated with the deviation from the verb's general tendency of complementizer selection. the three t-sne plots that we have analyzed in this section demonstrate the value of inspecting divergent clusters: the inspection allows researchers to identify the characteristics of clusters which do not follow a verb's general embedding tendency. the ability to do this is of high importance both for nlp purposes and for l2 instruction. in both cases, knowing the general tendency is helpful: in nlp, this allows us to build stronger parsers which are informed by this expectation and which utilize the expectation when disambiguating the sentence tokens; and for l2 learners, knowing the general verb-complementizer pairings can allow them to formulate their sentences in accordance with the expectations of native speakers. however, knowledge of the overarching tendency of a verb is only useful up to a point. given the clusters we have seen which highlight specialized usages, blind pursuit of the general tendency can lead one astray, whether for l2 language production or for nlp sentence parsing. instead, the key is to both know the general tendencies of the verbs, and also to know how to identify sentences groups in which those general tendencies do not apply, and may even be flipped. our t-sne plots provide an effective method to inspect the usage of the verb overall, and to hone in on examples that constitute specialized usages. of course, to the extent possible, we prefer to automatically quantify the extent to which a verb's overall tendency regarding complementizer selection will apply consistently across the full range of its uses, without the need to resort to manual inspection of t-sne plots. in order to do so, we run an automatic clustering routine on the sentences of a given verb, as described above, and we then calculate the jensen-shannon divergence (jsd) of each substantially-sized cluster in order to identify divergences. we utilize this method to calculate corpus-based complementizer statistics for the 100 most frequent complement-taking verbs in contemporary hebrew. the first part of the table is presented here ( for each verb, we first present the overall statistical tendency towards one or the other of the complementizers, and we note the number of sentences that the statistics were based upon. additionally, we measure the extent to which the statistical tendency holds true across the corpus, and the extent to which we find specialized usages of the verb in which the tendency is exaggerated or flipped. regarding many of the verbs, the last three columns contain zeroes, indicating that the overall balance between the two complementizers remains stable for the given verb across the corpus. in contrast, other verbs reveal specialized clusters to greater or lesser degrees. for instance, for the verb biqeš ('asked'), the first few columns indicate that in general šeis far more likely; at the same time, in 10% of the cases, there is a much stronger affinity to ki. on the flipside, regarding hepešim ('accused'), the preference is generally towards ki, but 14% of the sentences cluster into groups in which the tendency is flipped toward šeinstead. finally, some verbs split in both directions. for instance, for amar ('said'), the overall statistics point to balanced usage between the two complementizers, but the divergence columns indicate that, in fact, the usage is often not balanced at all: 21% of the sentences are in clusters that show a specific preference for ki, and 16% of the sentences are in clusters that show a preference for še-. in other words, in over a third of the corpus, it is not the case that the two complementizers are equally interchangeable, but rather, the varying contexts in which amar occurs determine which complementizer is expected. ## unusual complementizers in hebrew literature as explained above in section 3.3, we propose the use of complementizer clusterings in order to identify places in which literary authors deviate from the norm. we analyze all instances of clausal complements within a corpus of novels by the modern israeli author amos oz (see our first example, in (6), exemplifies an unexpected use of ki in a story by oz @xcite ): (6) biršuta with.her.permission agid will.say.1sg la to.her ki comp lo not beit marzeax tavern kan here the use of the complementizer ki with the verb 'told' is exceedingly rare in general. as we saw above, the one cluster in which this verb is naturally used with ki is when the statement is impersonal, with the subject generally unspecified. yet, the statement in (6) could hardly be more personal; it is phrased in the first person, with a personal plea at the beginning ('please my lady' introduces the sentence we see here). the use of ki as a complementizer in this context conflicts with the reader's expectations, and characterizes the statement as subtly unusual. and, indeed, in this paragraph, oz wishes to paint this characterdescribed in the book as an "elderly poet" -as one who interacts with fairly archaic hebrew expression. in addition to the originally biblical ki, in the continuation of the paragraph, this character uses a number of other archaic (biblical or talmudic) words and phrases, such as the negative interrogative ‫הלא‬ hȃlō, as well as ‫אימתי‬ peymatay ('when'), and ‫אדע‬ ‫כי‬ ‫אנוכי‬ ‫מי‬ mī pōnōk ¯ī kī pēdaq ('who am i to know'). the coupling of the verb 'told' with the complementizer ki, while exceedingly unusual for contemporary hebrew, is in fact well-attested in biblical hebrew (e.g. genesis 3:11, genesis 31:20, psalms 92:16, and more). oz's selection of this complementizer is thus clearly deliberate, serving to help characterize the biblical idiom of the "elderly poet". the complementizer šeis the more general of the two complementizers (no verb exclusively selects ki, as can be seen in the table in appendix a) and is often thought to be a general-purpose complementizer in hebrew. however, not all uses of šeare equally felicitous. example (7) is highlighted by our procedure as an unexpected use of the complementizer šein oz's prose @xcite ): (7) ve-od and-more raciti wanted.1sg lehodiaqaxa to.inform.you še-me-ha-mixtav that-from-the-letter še-šalaxta that-sent.2msg lanu to.us imxa your.mother baxta cried bi-dmaqot in-tears 'and i also wanted to inform you that your mother wept in tears from the letter you sent us.' in general, the preferred complementizer with the verb hodiqa ('inform') is ki -74% across the whole corpus. moreover, this particular sentence is classified as part of a cluster in which the preference for ki is far more extreme: over 95%. the cluster includes multiple specimens of the verb with a second-person pronominal suffix, as we find in oz's novel. such phrases are typical of formal and legal documents, which dish out an objective and impersonal ruling; hence the overwhelming preference for ki. yet, oz's context is not legal at all. rather, it is from a letter written by a woman's second husband, in which he struggles to connect with his step-son, a boy portrayed as unruly and rough, both in character and in his use of language. oz's formulation reflects the letterwriter's struggle in this endeavor. on the one hand, the sentence begins with the highly formal legalese "to inform you" -a phrasing that normally creates a distanced atmosphere. yet, the unexpected choice of the less-formal complementizer can be seen as an attempt to step back and make the message more accessible to the boy, more personal and more sensitive. in sum, our method identifies cases where a hebrew literary master makes a complementizer choice that goes against the grain of how attitudes are usually expressed, inviting further literary analysis to suggest what may have motivated the oddity. ## conclusion this paper demonstrates a language-agnostic method to run a large-scale corpus-based investigation of complementizer variability. we show how this method can be used to isolate cases where authors deviate strikingly from an expected complementizer; such aberrations may well reflect a deliberate literary choice, and invite literary analysis. we apply this method to contemporary hebrew. this is the first time that hebrew complementizers have been investigated from a large-scale corpus-based perspective. contra the perceived view about hebrew, we find that the language does have grammatical marking of mood: not in the verbal morphology, but in its subordinating particles. moreover, there is not a true subset relation between the uses of the two complementizers; there are verbs that strongly prefer ki and allow šeonly under highly specific contexts. we provide results for complementizer selection regarding the top 100 clause-embedding verbs in contemporary hebrew. we expect that this first-of-its-kind lexical resource will comprise a helpful resource both for l2 learners, as well as for hebrew nlp researchers.