Vietnamese Word Sketches

Word sketches are one-page automatic, corpus-based summaries of a word's grammatical and collocational behaviour. They were first used in the production of the Macmillan English Dictionary (Rundell 2002). At that point, word sketches only existed for English. Today, the Sketch Engine is available, a corpus tool which takes as input a corpus of any language and corresponding grammar patterns and which generates word sketches for the words of that language. It also automatically generates a thesaurus and 'sketch differences', which specify similarities and differences between nearsynonyms. A web corpus of Vietnamese was tokenized, part-of-speech-tagged and loaded into the Sketch Engine. The results show that word sketches could significantly facilitate lexicographic work for Vietnamese, as they have for other languages. The word sketches, for Vietnamese and many other languages, can be seen at http://www.sketchengine. co.uk. Word sketches are one-page automatic, corpus-based summaries of a word's grammatical and collocational behaviour. Their value for lexicographic work in English and other languages, as well as the background of the use of corpora in lexicography, have been described elsewhere (Kilgarriff and Rundell 2002, Kilgarriff et al. 2004). A variety of corpus query systems (CQSs) have been used to examine corpus evidence since the rise of the first electronic corpora. Starting with the ground-breaking COBUILD project, lexicographers have been using KWIC (Key Word In Context) concordances as their primary tool for finding out how a word behaves. Later, with the growth of corpora, lexical statistics had to be applied to manage the abundant data and highlight the most salient collocations. Today, state-of-the-art CQSs allow the lexicographer great flexibility in searching for phrases, collocates, grammatical patterns, sorting concordances according to a wide range of criteria, selecting subcorpora for searching in, say, only spoken text, academic text, or only fiction. Available systems include WordSmith (Scott 2008) and the Stuttgart Corpus Workbench (CWB, Christ and Schulze 1994), and the Sketch Engine. The Sketch Engine (http://www.sketchengine.co.uk) is a corpus query system which gives access to the familiar CQS functions: concordances for several types of queries (simple, lemma, phrase, word form and CQL), with an integrated context control filter (Fig. 1). Fig. 1: The Sketch Engine concordancer query window The features of the Sketch Engine which are of special interest in this paper are not part of standard concordancing programs. These features include word sketches, sketch differences and a thesaurus. They are all fully integrated with standard concordancing. A word sketch is a one-page automatic, corpus-based summary of a word's grammatical and collocational behaviour. A word sketch for Vietnamese tay (‘hand’) is given in Fig. 2. Fig. 2. Word sketch for Vietnamese tay. To create the word sketch, the Sketch Engine needs to know how to identify words connected by a grammatical relation. This can be achieved in one of two ways. The first possibility is to parse the input corpus, so that the information about which word-instances stand in which grammatical relations with which other word-instances is embedded in the corpus. Currently, dependency-based syntactically annotated corpora are supported. We need to mark heads of phrases in phrase structure trees. In the second approach, the input corpus is loaded into the Sketch Engine part-of-speech-tagged but not parsed, and the Sketch Engine supports the process of identifying grammatical relation instances through a sketch grammar. Grammatical relations (or gramrels, for short) will be defined one by one, using the Sketch Engine to test and develop them. Once the developer is satisfied with the definition of each grammatical relation, they save the file and the Sketch Engine then compiles it, finding all instances of all grammatical relations in the corpus. It puts them in a gramrels database, which gives users access to word sketches. Grammatical relations are defined as regular expressions over part-of-speech (POS) tags, using the CQL formalism as first specified within the Stuttgart Corpus Wordbench and extended in Jakubíček et al (2010).