Content Differences in Syntactic and Semantic Representations

Syntactic analysis plays an important role in semantic parsing, but the nature of this role remains a topic of ongoing debate. The debate has been constrained by the scarcity of empirical comparative studies between syntactic and semantic schemes, which hinders the development of parsing methods informed by the details of target schemes and constructions. We target this gap, and take Universal Dependencies (UD) and UCCA as a test case. After abstracting away from differences of convention or formalism, we find that most content divergences can be ascribed to: (1) UCCA's distinction between a Scene and a non-Scene; (2) UCCA's distinction between primary relations, secondary ones and participants; (3) different treatment of multi-word expressions, and (4) different treatment of inter-clause linkage. We further discuss the long tail of cases where the two schemes take markedly different approaches. Finally, we show that the proposed comparison methodology can be used for fine-grained evaluation of UCCA parsing, highlighting both challenges and potential sources for improvement. The substantial differences between the schemes suggest that semantic parsers are likely to benefit downstream text understanding applications beyond their syntactic counterparts.Comment: NAACL-HLT 2019 camera read

The Crosslinguistic Relationship between Ordering Flexibility and Dependency Length Minimization: A Data-Driven Approach

This paper asks whether syntactic constructions with more flexible constituent orderings have a weaker tendency for dependency length minimization (DLM). For test cases, I use verb phrases in which the head verb has one direct object noun phrase (NP) dependent and exactly on adopositional phrase (PP) dependent adjacent to each other on the same side (e.g. Kobe prasied [NP his oldest daughter] [PP from the stands]). Data from multilingual corpora of 36 languages show that when combining all these languages together, there is no consistent relationship between flexibility and DLM. When looking at specific ordering domains, on average there appears to be a weaker preference for shorter dependencies in constructions with more flexibility mostly in preverbal contexts, while no correlation exists between the two in postverbal domains

What Did You Expect? An Investigation of Lexical Preactivation in Sentence Processing

Language users predictively preactivate lexical units that appear to the comprehen- der to be likely to surface. Despite ample language experience and grammatical competence, it appears that language users tend to preactivate verbs in some contexts, called role-reversal contexts, that would create plausibility violations if they were to actually appear; these verbs assign thematic roles to their arguments in such a way that it leads to implausibility. These anomalous predictions provide a window into the mechanisms underlying lexical preactivation and are the case study that this dissertation focuses in on. This dissertation is an exploration of what linguistic information is effectively leveraged to modulate lexical expectations in sentence and discourse contexts (both appropriate and anomalous) and a comparison of the methodologies that are common to test for lexical preactivation. Using a series of cloze experiments, I will argue that these anomalous predictions are the result of two mechanisms that co-contribute to spread preactivation to role- anomalous verbs. The first is a small but non-negligible “Bag of Words” associative priming mechanism, and the second is a more sophisticated mechanism that prioritizes pre-verbal arguments that are unsaturated, that is they are in need of a predicate, that I am calling a “Bag of not yet Saturated Arguments” mechanism. Though lexical predictions derived from sentence compositional meanings are indeed the most common, these less sophisticated mechanisms play an important role in lexical preactivation and contribute to the preactivation of both role-appropriate and role-anomalous verbs in real- time sentence processing. By comparing cloze responses and reading times, I also argue in this dissertation that participants make both position-specific predictions, predictions about what words may occur in position n+1, and predictions that are expected to surface merely sooner-or-later in the context. I additionally argue that the N400 and eye tracking measures such as the first fixation duration are particularly reflective of this latter type of prediction, while cloze responses are less so. This explains the discrepancies observed between these common measures of lexical preactivation in role-reversed sentences

The Role of Frequency in the Processing of giving and receiving Events in Korean

This study aimed to examine the processing benefits of frequency information associated with the case marker -eykey in comprehending Korean declarative sentences. By using a picture description task in which pictures ambiguously illustrated either a giving event (-eykeyREC … cwuta give … to) or a receiving event (-eykeySOURCE … patta receive … from), we found that giving events were predominantly preferred to receiving events. The results of the online sentence comprehension study revealed that 1) give-type verbs were integrated into sentences faster than receive-type verbs overall and 2) the reading-time differences between the verb types were significant when role NPs were canonically ordered (NP-eykey … NP-(l)ul) but not when they were noncanonically presented (NP-(l)ul … NP-eykey). We claim that structural and semantic frequency bias associated with -eykey facilitates readers anticipatory processing in the integration of upcoming information. We further discuss how the processing differences in giving and receiving events might attribute to the argument-adjunct distinction between recipients and sources

Eesti keele kohakäänded argumendistruktuuris

Keele rääkijatena ei teadvusta me endale sageli, et kui me kasutame tegusõnu, siis nendega käivad kaasas teatud käänded, mis sõltuvad sellest tegusõnast, mida kasutati. Vaatad telekat? Sõna „telekas“ ilmub osastavas käändes. Sööd pitsat või sõid pitsa ära? Osastav või omastav kääne. Unistad millestki? Seestütlev kääne. Me teame, millist käänet kasutada, aga me ei tea, miks me seda teeme. Miks on tegusõnade ja käänete süsteem selline nagu ta on ja miks kasutame mõnede tegusõnadega kohakäändeid, kui nad ei tähista seal asukohti – näiteks „unistan pitsast“ või „pidu järgneb õhtusöögile“?Tegusõna kirjeldab sündmust või seisundit, millel üldiselt on osalised. Fraase, mis väljendavad neid osalisi, nimetame tegusõna argumentideks. Näiteks „sööma“ argumendid on see, kes sööb, ja see, mida süüakse. Ilma nendeta poleks sel tegusõnal tähendust. Nende kahe fraasi käänded sõltuvad tegusõnast. Igal tegusõnal on seega argumendistruktuur, ehk struktuur kindlate käänetega teatud konfiguratsioonis, mille abil saame teada, kes või mis osales verbi kirjeldatud sündmuses ja millises rollis nad seda tegid. „Vaatama“ kasutab argumendistruktuuri nimetavas käändes vaatajaga ja osastavas käändes vaadatavaga. „Unistama“ kasutab aga struktuuri, kus unistaja on nimetavas ja unistamise objekt seestütlevas käändes.Käesolev monograafia kirjeldab kuue kvantitatiivsete korpusuuringu ja ühe katse tulemusi, mille abil uuriti, milline roll on eesti keeles kohakäänetega argumendistruktuuridel. Töö uurib kohakäänetega struktuuride kolme aspekti – nendega ilmuvaid tegusõnu, nendes ilmuvaid käändeid ja nende märgitud argumendistaatuse tugevust.Esiteks, on põhjust arvata, et teatud struktuurid ilmuvad vaid teatud tüüpi tegusõnadega, kuid pole selge, kuidas täpselt erinevad eesti keeles eri struktuuride tegusõnad üksteisest. Käesolev töö leidis, et kohakäändestruktuuridega ilmuvad tegusõnad viitavad palju staatilisematele oludele kui tavapärase osastava või omastava struktuuriga tegusõnad, kirjeldades pigem seisundeid kui sündmusi. Samuti leidis see, et enamjaolt ei ole kohakäänetel sellises positsioonis enam kohatähendust, isegi mitte metafoorselt.Teiseks, töö uuris, kui grammatiseerunud on kuus eesti keele kohakäänet. Kõrgem grammatiseerumistase viitab laialdasemale kasutusele argumendimarkerina ning käände sagedasemale kasutusele kohatähenduseta kontekstides. Töö leidis, et seestütlev ja alaleütlev kääne on nii grammatiseerunud, et eesti keele rääkijad kasutavad neid pigem ilma kohatähenduseta, sealhulgas tähistamaks sündmuste ja seisundite osalisi.Kolmandaks, monograafia keskendub argumendisideme tugevusele tegusõna ja argumendi vahel. Keeleteaduses arvatakse, et grammatilises (nt osastavas) käändes argumendid („sööb leiba“) on tugevamad argumendid kui kohakäändes argumendid („unistab leivast“). Esimest tüüpi argumente loetakse eesti keeles sihitiseks, aga teist tüüpi ei loeta. Töö jaoks läbi viidud katse näitab, et argumendiside on neis kahes kontekstis sama tugev ega sõltu käändest. Katse näitas ka, et argumendistaatus on oma olemuselt gradientne mitte binaarne, ning et mõned asukohafraasid on tegusõnadega nii tugevalt seotud, et neid võib lugeda poolargumentideks.Kokkuvõttes annab väitekiri meile hulga uusi teadmisi sellest, kui lai võib olla kohakäänete kasutusala, millist tüüpi argumente nad markeerivad ning kuidas nad diakroonilises perspektiivis sellise funktsioonini jõuavad. Töö tulemused on vägagi relevantsed keelteüleses perspektiivis, arvestades morfoloogiliselt rikaste keelte (nt eesti keel) olulisust käänete ja nende süntaktilise funktsiooni uurimisel.Language speakers are not often aware of the fact that using certain verbs requires the use certain case affixes. The Estonian verb “vaatama“ (“watch“) requires its object to be in partitive case while “unistama” (“dream about”) takes an argument in elative case (“out of”). Speakers intuitively know which case to use, but they do not know what is behind this distrubution. What are the inner dynamics of the system around verbs and cases? How often and on what conditions are spatial cases (e.g. elative) used with verbs when they do not express spatial meaning, for instance “Ma unistan pitsa-st” (“I am dreaming about pizza”). Do they mark essentially the same type of argument status as grammatical cases (e.g. partitive)?Verbs express events or states that commonly have participants. Phrases referring to these participants are known as verbal arguments. For instance, “sööma” (“eat”) takes two arguments – the eater and the eaten. Without them, the verb would not have meaning. The cases on these two phrases depend on the verb. Each verb therefore has an argument structure, i.e. selects particular cases in a particular configuration, letting us know, what is involved in the event described by the verb, and in what type of role they play. “Vaatama” (“watch”) has a structure with a nominative subject and a partitive object. The structure of “unistama” (“dream about”), however, includes a nominative subject and an elative argument.This thesis presents six corpus studies and one experiment, all investigating Estonian argument structures with spatial cases. It focusses on the three main variables describing argument structures: the verbs with which they occur, the cases they include and the strength of argument status they mark.First, there is reason to think that different structures occur with different types of verbs. It is not clear, however, in what ways these verbs are distinct in Estonian. We found that verbs in spatial case argument structures (“unistama” – “dream about”) are more stative than verbs in more common argument structures (“sööma” – “eat”). We also found that in a wide range of verbs, spatial cases no longer have any trace of spatial meaning when marking their arguments.Second, we asked, which spatial cases are most grammaticalised. Cases on a higher grammaticalisation level mark arguments and occur without spatial meaning more frequently. We found that elative (“out of”) and allative (“onto”) are so grammaticalized that they are infrequently used for referring to space. Instead, they are used for talking about other types of meaning and relationships, including marking the highly abstract argument relation.Third, the thesis investigated argument status in various functions of spatial cases. Mainstream linguistic theory regards canonical objects (e.g. the object of “eat”) as stronger arguments than non-canonical arguments (e.g. the elative argument of “unistama” – “dream about”). Our experiment showed that spatial case structures include equally strong arguments as canonical structure, meaning case has little to do with argument status. It also demonstrated the gradient nature of argument status, outlining various types of semi-arguments.All in all, the thesis provides us with an abundance of new knowledge about how Estonian spatial cases function in the service of verbs. These results are highly relevant to cross-linguistic knowledge, given the important role morphologically rich languages such as Estonian play in studies investigating the use of morphology in marking syntactic relations.https://www.ester.ee/record=b552789

Electrophysiological indices of syntactic processing difficulty

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, 1998.Includes bibliographical references (leaves [135]-[136]).Two types of processing difficulty are examined by means of electrical recordings taken from the scalp. One type of difficulty seems to be related to syntactic structural anomalies and another is related with memory load due to syntactic complexity. An experiment dealing with structural difficulty reveals the sensitivity of the parser with the argument status of the elements being processed. Memory constraints come into play when processing complex but structurally sound text strings. A number of experiments in this thesis examine a purported metric of complexity, namely, a left anterior negativity. It is argued that the predictive aspects of the parser is responsible for the complexity metric.by Anthony R. Harris.Ph.D