Language and Logic advanced course:
Advances in Abstract Categorial Grammars: Language theory and linguistic modeling.
Course material: esslli-acg-week-2.pdf
The abstract categorial grammar (ACG) (de Groote 2001), a grammar formalism based on the typed lambda calculus, elegantly generalizes and unifies a variety of grammar formalisms that have been proposed for the description of formal and natural languages. The first part of this course investigates formal-language-theoretic properties of "second-order" ACGs, a subclass of ACGs that have "context-free" derivations. Their generative capacity is precisely characterized, and an efficient Earley-style algorithm is presented. The second part of the course turns to linguistic applications of ACGs and gives various illustrations of how ACGs provide flexible and explicit ways to model the syntax-semantics interface of natural language.
Language and Logic workshop:
New Directions in the Theory of Presupposition.
The last ten years has seen a wealth of new developments on the topic of presupposition and, in particular, the projection problem for presupposition. While there had been considerable interest in the seventies in developing entirely pragmatic accounts of presupposition triggering and projection (Wilson, 1974, Stalnaker 1977, Grice, 1981), these accounts had generally not been sufficiently developed to match the dynamic accounts developed in the eighties in predictive power. Recent work, such as that of Schlenker (2006, 2008), however, has shown that broadly pragmatic accounts can also have considerable predictive power. In addition, trivalent approaches based on such techniques as supervaluations and the Strong Kleene connectives, which were dismissed by many long ago, have recently attracted new interest (Beaver and Krahmer, 2001, George, 2008, Fox, 2008) and have been shown capable of handling many empirical issues in presupposition projection. Thus there is no longer a clear consensus on how we should explain presupposition projection. In addition, experimental work has raised interesting questions about what the basic facts of presupposition projection are and suggests that real empirical work is needed to determine some of the subtleties (Chemla 2007). There has also been renewed interest in the triggering problem (Simons, 2001, Abusch, 2002) which naturally links up to the projection problem, as well as recent theoretical work on foundational issues such as the notion of common ground and accommodation (Beaver and Zeevat, 2004, von Fintel, 2001, 2006, Stalnaker, 2002). The purpose of this workshop is to bring together researchers on presupposition to discuss these new developments and connect some of the different theoretical and empirical questions, which are too often considered in isolation.
Language and Computation introductory course:
Intelligent Computer-Assisted Language Learning: An introduction to an emerging interdisciplinary field.
Intelligent Computer-Assisted Language Learning (ICALL) is a relatively young field of interdisciplinary research exploring the integration of natural language processing in foreign language teaching. The course will introduce both the theoretical issues and the practical system development aspects of ICALL and provide the student with a firm basis for understanding the current research issues. Key questions discussed include the following: Where does ICALL fit into foreign language teaching? Why are notions such as noticing and awareness from cognitive psychology important for second language acquisition and ICALL research? How can natural language processing (NLP) be adapted to process learner language? What are the challenges for NLP in detecting properties of learner language and what is know about presenting feedback to learners? What are learner models and what roles do they play in ICALL systems? And last but not least, how can shallow semantic NLP analysis be used to provide feedback on meaning in addition to feedback on form, and why is this important?
Language and Computation advanced course:
Linguistic Information Visualization.
Course material: carpendale_penn.pdfAbstract:
Much of what computational linguists fall back upon to improve
natural language processing and model language "understanding" is
structure that has, at best, only an indirect attestation in
observable data. The sheer complexity of these structures, and
the observable patterns on which they are based, however, usually
limits their accessibility, often even to the researchers creating
or studying them. Traditional statistical graphs and
custom-designed data illustrations fill the pages of CL papers,
providing insight into linguistic and algorithmic structures, but
visual 'externalizations' such as these are almost exclusively
used in CL for presentation and explanation.
Visualizations can also be used as an aid in the process of research itself. There are special statistical methods, falling under the rubric of "exploratory data analysis", and visualization techniques just for this purpose, in fact, but these are not widely used or even known in CL. These novel data visualization techniques offer the potential for creating new methods that reveal structure and detail in data. Visualization can provide new methods for interacting with large corpora, complex linguistic structures, and can lead to a better understanding of the states of stochastic processes.
Instructed by a team of computational linguists and information visualization researchers, this tutorial will bridge computational linguistic and information visualization expertise, providing attendees with a basis from which they can begin to leverage information visualization in their own research. It will equip participants with: - An understanding of the importance and applicability of information visualization techniques to computational linguistics research; - Knowledge of the basic principles of information visualization theory; - The ability to identify appropriate visualization software and techniques that are available for immediate use and for prototyping; - A working knowledge of research to date in the area of linguistic visualization.
This tutorial will be an extended version of the 3-hour tutorial offered at ACL-2008, which had 25 attendees. The instructors have previously taught portions of the content in advanced undergraduate and graduate courses as well. Students are expected to have a solid background in computational linguisics. No experience with visualization is required.
Day 1: Introduction; Information Visualization Theory (representational theory, cognitive psychology, preattentive processing, interaction & animation, assessing and validating visualizations)
Days 2 and 4: Review of Linguistic Visualizations (document content visualizations, text collection analysis, literary analysis, streaming data visualization, convergence of linguistic data and social network analysis, corpora exploration, visualization uncertainty in statistical NLP output, linguistic analysis, visualization of speech data)
Day 3: Tools for Visualization (software solutions: Excel, Tableau, Spotfire, programming toolkits: prefuse, processing, flare, InfoVis Toolkit, online tools: ManyEyes, Swivel, collaborative visualization tools in development)
Day 5: Case Study: Visualization for Statistical MT; Open Research Problems (CL problems that could benefit from visualization, Visualization of language areas that need CL expertise); Closing
Logic and Computation advanced course:
Dynamic Logics for Interactive Belief Revision.
This course is addressed to students and researchers interested in logics for reasoning about multi-agent belief revision, belief updates and knowledge updates induced by various forms of communication or interaction. It is a foundational course, designed to present to students and researchers from other fields the work done in recent years by a number of researchers on integrating ideas from Belief Revision Theory within the DEL (Dynamic-Epistemic Logic) paradigm. The course is self-contained, not assuming any background knowledge, but presupposing only some general experience or facility with using logical languages, the concepts of syntax and semantics etc. We start by presenting the main notions of "standard DEL", arguing that this logic is appropriate for updating "hard information" (unrevisable knowledge), but that it is inappropriate for "soft information" (possibly false beliefs or defeasible knowledge). We then present "belief-revision models", defining some important epistemic/doxastic notions, considering a number of logical languages for these models, and explaining the relevance of these notions to fundamental issues in contemporary Epistemology, in Computer Science and in the study of language and communication. We present various Belief Update operations and various belief-revision policies proposed by different authors, focusing on one particular proposal (the Action-Priority Update) of great generality and elegance. We present reduction laws (the "dynamic laws of Interactive Belief Revision"), complete axiomatizations, applications to dialogue games and communication strategies, connections with other research areas and open problems.
Language and Logic introductory course:
Syntax and Semantics from an Algebraic Perspective.
Developing perspectives from Keenan and Stabler (2003), this class will explore algebraic methods for compositionally defining and comparing various languages (syntax and semantics), with particular attention to various constructions with quantification and binding in the world's languages.
Introduction: Language structure (!=trees) and universals (!=fixed constituent orders). A universal of anaphor binding.
Evans and Levinson (BBS, forthcoming) take Chomskyan linguistics to task for insufficient recognition of the diversity of human languages. This diversity, they claim, renders universal claims few in number and largely trivial in content, whence the monolithic picture of Universal Grammar that generative grammarians present to the CogSci community at large is inaccurate and misleading. Our response to this critique exhibits a novel format of universal generalization that has the mathematical rigor desired (if not always achieved) by a Chomskyan approach, but which incorporates (morpho)syntactic diversity in an essential way. More important than diversity per se is that languages exhibit non-universal structural regularities that speakers must learn. We illustrate this with universal claims concerning anaphora -- one of the areas in which E+L criticize the Chomskyan approach
Example 1: Affixes and structure in Malagasy, without movement.
Example 2: Quantification in 'minimalist grammar', with movement. A 'directly compositional' semantics for a grammar with 'quantifier raising'.
Language similarity 1: Stable automorphisms; perspectives on probabilistic language models.
Language similarity 2: Homomorphic realizations of canonical patterns of predication, modification, and binding.