435 research outputs found
Computational Approaches to the Syntax–Prosody Interface: Using Prosody to Improve Parsing
Prosody has strong ties with syntax, since prosody can be used to resolve some syntactic ambiguities. Syntactic ambiguities have been shown to negatively impact automatic syntactic parsing, hence there is reason to believe that prosodic information can help improve parsing. This dissertation considers a number of approaches that aim to computationally examine the relationship between prosody and syntax of natural languages, while also addressing the role of syntactic phrase length, with the ultimate goal of using prosody to improve parsing.
Chapter 2 examines the effect of syntactic phrase length on prosody in double center embedded sentences in French. Data collected in a previous study were reanalyzed using native speaker judgment and automatic methods (forced alignment). Results demonstrate similar prosodic splitting behavior as in English in contradiction to the original study’s findings.
Chapter 3 presents a number of studies examining whether syntactic ambiguity can yield different prosodic patterns, allowing humans and/or computers to resolve the ambiguity. In an experimental study, humans disambiguated sentences with prepositional phrase- (PP)-attachment ambiguity with 49% accuracy presented as text, and 63% presented as audio. Machine learning on the same data yielded an accuracy of 63-73%. A corpus study on the Switchboard corpus used both prosodic breaks and phrase lengths to predict the attachment, with an accuracy of 63.5% for PP-attachment sentences, and 71.2% for relative clause attachment.
Chapter 4 aims to identify aspects of syntax that relate to prosody and use these in combination with prosodic cues to improve parsing. The aspects identified (dependency configurations) are based on dependency structure, reflecting the relative head location of two consecutive words, and are used as syntactic features in an ensemble system based on Recurrent Neural Networks, to score parse hypotheses and select the most likely parse for a given sentence. Using syntactic features alone, the system achieved an improvement of 1.1% absolute in Unlabelled Attachment Score (UAS) on the test set, above the best parser in the ensemble, while using syntactic features combined with prosodic features (pauses and normalized duration) led to a further improvement of 0.4% absolute.
The results achieved demonstrate the relationship between syntax, syntactic phrase length, and prosody, and indicate the ability and future potential of prosody to resolve ambiguity and improve parsing
Recommended from our members
Syntax-Prosody Interactions in Irish
This dissertation is an empirical and theoretical study of sentence-level prosody in Conamara (Connemara) Irish. It addresses the architecture of the syntax-phonology interface and the relation between syntactic constituent structure and prosodic structure formation. It argues for a fully interactional view of the interface, in which the phonological form may be influenced by a number of competing factors, including constraints governing syntax-prosody correspondence, linearization, and prosodic well-formedness. The specific proposal is set within the framework of Match Theory (Selkirk 2009, 2011), an indirect-reference theory of the syntax-prosody interface in which correspondence between syntactic and prosodic constituents is governed by a family of violable Match constraints. These constraints call for a one-to-one correspondence between syntactic and prosodic structure, to the extent that prosodic structure may be recursive under pressure from the recursive nature of syntactic phrases. However, this direct correspondence can be overruled by other interacting constraints, including prosodic markedness constraints and, as proposed here, other correspondence relations, as on the linearization of hierarchical syntactic structures. This dissertation argues that the distribution of pitch accents in Conamara Irish provides direct evidence for Match Theory. It is proposed that two phrasal pitch accents, L-H and H-L, demarcate the edges of phonological phrases, where L-H accents specifically target only those phrases which are recursive. Using the distribution of these pitch accents as indicators for the presence of prosodic boundaries, the dissertation investigates a variety of syntactic structures in both the clausal and nominal domain. It is argued that there is a close correspondence between syntactic and prosodic structure in default cases, but that this direct correspondence may be subverted in favour of a structure which better satisfies higher-ranked prosodic markedness constraints. Finally, this dissertation addresses pronoun postposing, a process pervasive in Irish dialects in word order appears to be sensitive to prosodic structure. This dissertation proposes to account for this phenomenon using the theoretical framework developed in the dissertation, in which the main patterns are accounted for through the interaction of Match constraints, prosodic markedness constraints, and a proposed violable constraint on the linearization of syntactic structure
A detection-based pattern recognition framework and its applications
The objective of this dissertation is to present a detection-based pattern recognition framework and demonstrate its applications in automatic speech recognition and broadcast news video story segmentation.
Inspired by the studies of modern cognitive psychology and real-world pattern recognition systems, a detection-based pattern recognition framework is proposed to provide an alternative solution for some complicated pattern recognition problems. The primitive features are first detected and the task-specific knowledge hierarchy is constructed level by level; then a variety of heterogeneous information sources are combined together and the high-level context is incorporated as additional information at certain stages.
A detection-based framework is a â divide-and-conquerâ design paradigm for pattern recognition problems, which will decompose a conceptually difficult problem into many elementary sub-problems that can be handled directly and reliably. Some information fusion strategies will be employed to integrate the evidence from a lower level to form the evidence at a higher level. Such a fusion procedure continues until reaching the top level. Generally, a detection-based framework has many advantages: (1) more flexibility in both detector design and fusion strategies, as these two parts
can be optimized separately; (2) parallel and distributed computational components in primitive feature detection. In such a component-based framework, any primitive component can be replaced by a new one while other components remain unchanged; (3) incremental information integration; (4) high level context information as additional information sources, which can be combined with bottom-up processing at any stage.
This dissertation presents the basic principles, criteria, and techniques for detector design and hypothesis verification based on the statistical detection and decision theory. In addition, evidence fusion strategies were investigated in this dissertation. Several novel detection algorithms and evidence fusion methods were proposed and their effectiveness was justified in automatic speech recognition and broadcast news video segmentation system. We believe such a detection-based framework can be employed
in more applications in the future.Ph.D.Committee Chair: Lee, Chin-Hui; Committee Member: Clements, Mark; Committee Member: Ghovanloo, Maysam; Committee Member: Romberg, Justin; Committee Member: Yuan, Min
Tonal placement in Tashlhiyt: How an intonation system accommodates to adverse phonological environments
In most languages, words contain vowels, elements of high intensity with rich harmonic structure, enabling the perceptual retrieval of pitch. By contrast, in Tashlhiyt, a Berber language, words can be composed entirely of voiceless segments. When an utterance consists of such words, the phonetic opportunity for the execution of intonational pitch movements is exceptionally limited. This book explores in a series of production and perception experiments how these typologically rare phonotactic patterns interact with intonational aspects of linguistic structure. It turns out that Tashlhiyt allows for a tremendously flexible placement of tonal events. Observed intonational structures can be conceived of as different solutions to a functional dilemma: The requirement to realise meaningful pitch movements in certain positions and the extent to which segments lend themselves to a clear manifestation of these pitch movements
- …