EDBL: a General Lexical Basis for the Automatic Processing of Basque

EDBL (Euskararen Datu-Base Lexikala) is a general-purpose lexical database used in Basque text-processing tasks. It is a large repository of lexical knowledge (currently around 80,000 entries) that acts as basis and support in a number of different NLP tasks, thus providing lexical information for several language tools: morphological analysis, spell checking and correction, lemmatization and tagging, syntactic analysis, and so on. It has been designed to be neutral in relation to the different linguistic formalisms, and flexible and open enough to accept new types of information. A browser-based user interface makes the job of consulting the database, correcting and updating entries, adding new ones, etc. easy to the lexicographer. The paper presents the conceptual schema and the main features of the database, along with some problems encountered in its design and implementation in a commercial DBMS. Given the diversity of the lexical entities and the complex relationships existing among them, three total specializations have been defined under the main class of the hierarchy that represents the conceptual schema. The first one divides all the entries in EDBL into Basque standard and non-standard entries. The second divides the units in the database into dictionary entries (classified into the different parts-of-speech) and other entries (mainly non-independent morphemes and irregularly inflected forms). Finally, another total specialization has been established between single-word entries and multiword lexical units; this permits us to describe the morphotactics of single-word entries, and the constitution and surface realization schemas of multiword lexical units.A hierarchy of typed feature structures (FS) has been designed to map the entities and relationships in the database conceptual schema. The FSs are coded in TEI-conformant SGML, and Feature Structure Declarations (FSD) have been made for all the types of the hierarchy. Feature structures are used as a delivery format to export the lexical information from the database. The information coded in this way is subsequently used as input by the different language analysis tools

IRAKAZI: a web-based system to assess the learning process of Basque language learners

IRAKAZI is a teacher oriented web-based system designed for the study of Basque learners' learning process. The system involves a wide background in NLP tools, error detection and ICALL environments and it is easily transferable to other languages

Identificación de cláusulas y chunks para el Euskera, usando Filtrado y Ranking con el Perceptron

Este artículo presenta sistemas de identificación de chunks y cláusulas para el euskera, combinando gramáticas basadas en reglas con técnicas de aprendizaje automático. Más concretamente, se utiliza el modelo de Filtrado y Ranking con el Perceptron (Carreras, Màrquez y Castro, 2005): un modelo de aprendizaje que permite identificar estructuras sintácticas parciales en la oración, con resultados óptimos para estas tareas en inglés. Este modelo permite incorporar nuevos atributos, y posibilita así el uso de información de diferentes fuentes. De esta manera, hemos añadido información lingüística en los algoritmos de aprendizaje. Así, los resultados del identificador de chunks han mejorado considerablemente y se ha compensado la influencia del relativamente pequeño corpus de entrenamiento que disponemos para el euskera. En cuanto a la identificación de cláusulas, los primeros resultados no son demasiado buenos, debido probablemente al orden libre del euskera y al pequeño corpus del que disponemos actualmente.This paper presents systems for syntactic chunking and clause identification for Basque, combining rule-based grammars with machine-learning techniques. Precisely, we used Filtering-Ranking with Perceptrons (Carreras, Màrquez and Castro, 2005): a learning model that recognizes partial syntactic structures in sentences, obtaining state-of-the-art performance for these tasks in English. This model allows incorporating a rich set of features to represent syntactic phrases, making possible to use information from different sources. We used this property in order to include more linguistic features in the learning model and the results obtained in chunking have been improved greatly. This way, we have made up for the relatively small training data available for Basque to learn a chunking model. In the case of clause identification, our preliminary results are low, which suggest that this is due to the free order of Basque and to the small corpus available.Research partly funded by the Basque Government (Department of Education, University and Research, IT-397-07), the Spanish Ministry of Education and Science (TIN2007-63173) and the ETORTEK-ANHITZ project from the Basque Government (Department of Culture and Industry, IE06- 185)

Construcción de un corpus etiquetado sintácticamente para el euskera

El objetivo de este trabajo es la construcción de un corpus anotado sintácticamente para el euskera. En esta comunicación presentaremos, en primer lugar, las bases sobre las que se asienta nuestro etiquetado. Tras examinar diversas opciones se optó por el esquema presentado por (Carrol et al., 1998). Este esquema sigue los estándares EAGLES y se basa en la idea de añadir a cada frase del corpus una serie de relaciones gramaticales que especifican la dependencia existente entre el núcleo y sus modificadores. Una vez presentado el formalismo de etiquetado, se expondrán los problemas que hemos encontrado en nuestra tarea y las decisiones tomadas. Seguidamente se describirá un ejemplo concreto en el que se muestra la aplicación de dicho esquema sobre un corpus inicial. Finalmente, presentaremos las conclusiones sobre la idoneidad del esquema al euskera y trabajo futuro.The aim of this work is the construction of a syntactically annotated treebank for Basque. In this paper we present first, the basis of the annotation. After examining several options we chose the scheme presented in (Carrol et al., 1998). It follows the EAGLES standards and it is based on the idea of adding to each sentence in the corpus a series of grammatical relations specifying the dependencies between modifiers and their nucleus. After the formalism has been presented, we will describe the problems we have found and the decisions we have taken to solve them. Next we present an example showing the application of the scheme to an initial corpus. Finally, we present the main conclusions about the applicability to Basque and future work.Este trabajo se ha realizado dentro del proyecto "Construcción de una base de datos de árboles sintácticos y semánticos", subvencionado por el Ministerio de Educación y Ciencia (PROFIT: FIT-150500-2002-244)

Errores en el uso de determinantes en euskera: análisis y detección automática

En este artículo presentamos un estudio realizado para analizar el uso incorrecto de los determinantes en textos escritos en euskera. El análisis exhaustivo de esta tipología de errores (a través de los ejemplos recopilados) ha sido la base para la detección automática de los mismos. La recopilación y el análisis de errores son imprescindibles para el desarrollo de un corrector gramatical para el euskera y para la creación de sistemas inteligentes de enseñanza de lenguas asistida por ordenador (ICALL).In this paper we present the work carried out to deeply study the nature of determiner errors in written Basque. The collected error examples have led us to a more exhaustive analysis which has been essential for the automatic detection of the exhibited phenomena. The analyzed and stored data are necessary for the development of a grammar checker for Basque and Intelligent Computer-Assisted Language Learning (ICALL) systems