Morphological Tagging of a Spoken Portuguese Corpus Using Available Resources

This paper discusses the experience of reusing annotation tools developed for written corpora to tag a spoken corpus with POS information. Eric Brill’s tagger, initially trained over a written and tagged corpus of 250.000 words, is being used to tag the Portuguese C-ORAL-ROM spoken corpus, of 300.000 words. First, we address issues related with the tagset definition as well as the tagger performance over the written corpus. We discuss important options concerning the spoken corpus transcription, with direct impact on the tagging task, as well as the additional tags required. Transcription options allow in some cases for automatic tag identification and replacement, through a post-tagger process. Other cases, like the annotation of discourse markers, are more complex and require manual revision (and eventual listening). Since the final annotation will not only include the POS tag but also the wordform lemma, the paper also addresses issues related to the lemmatisation task. The positive results obtained show that the process of tagging and lemmatising a spoken Portuguese corpus through the reuse of already available resources may constitute an example of how to minimize the costs of such a task, without compromising the results. Finally, we discuss some possible developments to improve the tagger’s performance.info:eu-repo/semantics/publishedVersio

Providing on-line access to Portuguese language resources: corpora and lexicons

Several Language Resources (LRs) for Portuguese, developed at the Center of Linguistics of the Lisbon University (CLUL), are available on-line at CLUL’s webpage: www.clul.ul.pt/english/sectores/projecto_rld.html. These LRs have been extracted from or developed based on the Reference Corpus of Contemporary Portuguese(CRPC1), a monitor corpus containing, at the present, more than 350 million words, taken by sampling from several types of written text (literary, newspaper, technical, didactic, juridical, parlamentary, etc.) and spoken text (informal and formal), pertaining to national and regional varieties of Portuguese (including European, Brazilian, African and Asian Portuguese).The LRs available for on-line queries include: a) several subcorpora (written and spoken, tagged and untagged) compiled and extracted from CRPC for specific CLUL’s projects and now available for on-line queries; b) a published sample of “Português Fundamental”, a spoken CRPC subcorpus, available for texts download; c) a frequency lexicon extracted from a CRPC subcorpus available for both on-line queries and download. Other RLs available for Portugueseare also referred: C-ORAL-ROM - Integrated Reference Corpora for Spoken Romance Languages, a CD-ROM edition of a spoken corpus with text-to-sound alignment; the LE-PAROLE corpus; the LE-PAROLE Lexicon and the SIMPLE Lexicon.info:eu-repo/semantics/publishedVersio

On the use of comparable corpora of African varieties of Portuguese for linguistic description and teaching/learning applications

This presentation focuses on the use of five comparable corpora of African varieties of Portuguese (AVP), namely Angola, Cape Verde, Guinea-Bissau, Mozambique and Sao Tome and Principe, for multiple contrastive linguistic analyses and for the production of teaching and learning applications. Five contrastive lexicons have been corpus-extracted and further annotated with POS and lemma information and have been crucial to establish for each variety a core and peripheral vocabulary. Studies on AVP-specific morphological processes and on variation in verb complementation will also be discussed. These are first steps towards an integrated description of the five varieties and towards the elaboration of teaching and learning materials to be used by teachers of students from those five African countries with Portuguese as official language.info:eu-repo/semantics/publishedVersio

The Reference Corpus of Contemporary Portuguese and related resources

The extraordinary growth of computer applications, particularly over the last two decades, has enabled the easy compilation and exploration of large corpora and lexica. These linguistic resources play a fundamental role in the areas of theoretical linguistics and natural language engineering. Combining these two areas of knowledge can, in fact, result in the development of a large number of applications, such as new and straightforward descriptions of languages based on real data; contrastive studies between varieties of a particular language aiming at finding factors of unity and diversity; cross-linguistic contrastive studies; grammars; lexica and dictionaries; terminologies; assisted translation materials; language teaching materials; computer tools and applications for processing natural language. Having this principle in mind and following the tradition at the Centre of Linguistics of the University of Lisbon (CLUL)i of collecting and studying real language data, a large electronic corpus – the Corpus de Referência do Português Contemporâneo (Reference Corpus of Contemporary Portuguese, CRPC) – is being compiled at CLUL since 1988. The CRPC currently contains approximately 310 million words, searchable through a user-friendly interface, and it is envisaged as a monitor corpus (from which one can extract balanced subcorpora) that can serve as a sample of the Portuguese language (both in its written and spoken varieties). In the next sections, we will describe the CRPC and how it forms the basis for important resources developed at CLUL.info:eu-repo/semantics/publishedVersio

Lexical analysis of pre and post revolution discourse in Portugal

This paper presents a lexical comparison of pre (1954-74) and post (1974-94) revolution parliamentary discourse in four comparable sub-corpora extracted from the Reference Corpus of Contemporary Portuguese (CRPC). After introducing the CRPC, including annotation and meta-data, we focus on a subset of the corpus dealing with parliamentary discourses, more particularly a time frame of forty years divided into four comparable sub-corpora, each covering a ten-year period, two pre revolution and two post revolution. We extract lexical density information as well as salient terms pertaining to each period to make a comparative evaluation of the periods. Our results show how a linguistic analysis essentially based on the use of simple n-gram statistics can produce key insights into the use, change and evolution of the Portuguese language around a critical time period in its history.info:eu-repo/semantics/publishedVersio

A Lexical Database of Portuguese Multiword Expressions

This presentation focuses on an ongoing project which aims at the creation of a large lexical database of Portuguese multiword (MW) units, automatically extracted through the analysis of a balanced 50 million word corpus, statistically interpreted with lexical association measures and validated by hand. This database covers different types of MW units, like named entities, and lexical associations ranging from sets of favoured co-occurring forms with high corpus frequency and low cohesion to strongly lexicalized expressions with no, or minimum, variation. This new resource has a two-fold objective: to be an important research tool which supports the development of collocation typologies and their integration in a larger theory of MW units; to be of major help in developing and evaluating language processing tools able of dealing with MW expressions.info:eu-repo/semantics/publishedVersio

COMBINA-PT: a Large Corpus-extracted and Hand-checked Lexical Database of Portuguese Multiword Expressions

This paper presents the COMBINA-PT project, a study of corpus-extracted Portuguese Multiword (MW) expressions. The objective of this on-going project is to compile a large lexical database of multiword (MW) units of the Portuguese language, automatically extracted from a balanced 50 million word corpus, interpreted with lexical association measures and manually validated. MW expressions considered in the database include named entities and lexical associations with different degrees of cohesion, ranging from frozen groups, which undergo little or no variation, to lexical collocations composed of words that tend to occur together and that constitute syntactic dependencies, although with a low degree of fixedness. This new resource has a two-fold objective: (i) to be an important research tool which supports the development of MW expressions typologies and their lexicographic treatment; (ii) to be of major help in developing and evaluating language processing tools able of dealing with MW expressionsinfo:eu-repo/semantics/publishedVersio

Corpus-based extraction and identification of Portuguese Multiword Expressions

This presentation reports the methodology followed and the results attained on an on-going project aiming at building a large lexical database of corpus-extracted multiword (MW) expressions for the Portuguese language. MW expressions were automatically extracted from a balanced 50 million word corpus compiled for this project, furthermore statistically interpreted using lexical association measures and are undergoing a manual validation process. The lexical database covers different types of MW expressions, from named entities to lexical associations with different degrees of cohesion, ranging from totally frozen idioms to favoured co-occurring forms, like collocations. We aim to achieve two main objectives with this resource: to build on the large set of data of different types of MW expressions to revise existing typologies of collocations and to integrate them in a larger theory of MW units; to use the extensive hand-checked data as training data to evaluate existing statistical lexical association measures.Cet article présente la méthodologie suivie et les résultats obtenus dans le cadre d’un projet qui a pour objectif la construction d’une large base de données d’expressions multi-mots de la langue portugaise. Ces expressions multi-mots ont été automatiquement extraites d’un corpus équilibré de 50 millions de mots, interprétées statistiquement à l’aide de mesures d’association lexicales et ont été ensuite manuellement vérifiées. La base de données lexicales recouvre différent types d’expressions multi-mots avec différents degrés de cohésion, qui vont de la quasi totale fixité jusqu’aux groupes de mots qui se réalisent préférentiellement ensemble, comme les collocations. Le large ensemble de données de cette ressource permettra une révision des typologies d’unités multi-mots en portugais et l’évaluation de différentes mesures d’associations lexicales.info:eu-repo/semantics/publishedVersio

Open Resources and Tools for the Shallow Processing of Portuguese: the TagShare project

This paper presents the TagShare project and the linguistic resources and tools for the shallow processing of Portuguese developed in its scope. These resources include a 1 million token corpus that has been accurately hand annotated with a variety of linguistic information, as well as several state-of­the-­art shallow processing tools capable of automatically producing that type of annotation. At present, the linguistic annotations in the corpus are sentence and paragraph boundaries, token boundaries, morphosyntactic POScategories, values of inflection features, lemmas and named­ entities. Hence, the set of tools comprise a sentence chunker, a tokenizer, a POS tagger, nominal and verbal analyzers and lemmatizers, a verbal conjugator, a nominal “inflector”, and a named­-entity recognizer, some of which underline several on­line services.info:eu-repo/semantics/publishedVersio