Lexical Profiling of Environmental Corpora

Lexical Profiling of Environmental Corpora Patrick Drouin, Marie-Claude L’Homme, Benoˆıt Robichaud Observatoire de linguistique Sens-Texte (OLST) Universit´e de Montr´eal C.P. 6128, succ. Centre-ville Montr´eal (Qu´ebec) H3C 3J7 CANADA {patrick.drouin, mc.lhomme, benoit.robichaud}@umontreal.ca Abstract This paper describes a method for distinguishing lexical layers in environmental corpora (i.e. the general lexicon, the transdisciplinary lexicon and two sets of lexical items related to the domain). More specifically we aim to identify the general environmental lexicon (GEL) and assess the extent to which we can set it apart from the others. The general intuition on which this research is based is that the GEL is both well-distributed in a specialized corpus (criterion 1) and specific to this type of corpora (criterion 2). The corpus used in the current experiment, made of 6 subcorpora that amount to 4.6 tokens, was compiled manually by terminologists for different projects designed to enrich a terminological resource. In order to meet criterion 1, the distribution of the GEL candidates is evaluated using a simple and well-known measure called inverse document frequency. As for criterion 2, GEL candidates are extracted using a term extractor, which provides a measure of their specificity relative to a corpus. Our study focuses on single-word lexical items including nouns, verbs and adjectives. The results were validated by a team of 4 annotators who are all familiar with the environmental lexicon and they show that using a high specificity threshold and a low idf threshold constitutes a good starting point to identify the GEL layer in our corpora. Keywords: terminology, lexical layers, term extraction, corpora, environment 1. Introduction It is generally recognized that specialized texts comprise three main lexical layers: 1. terminology (the lexicon used to express domain-specific knowledge); 2. general lan- guage (the lexicon used by all speakers of a language and that is likely to be found in any kind of texts); and 3. a layer that lies in-between that will be called herein the transdisci- plinary lexicon (Drouin, 2007; Tutin, 2008; Hatier, 2016)1. We believe that in very large domains, such as the environ- ment that encompasses a broad variety of topics (climate change, sustainable development, renewable energy, wa- ter pollution, etc.), the terminology (defined above as the “domain-specific lexicon”) further divides into two layers. The first layer of the lexicon is topic specific. For instance, terms such as chlorination or marine turbine are specific to water pollution and renewable energy respectively. The second layer of the lexicon cuts across the entire field of the environment: e.g. ecosystem, sustainable, energy, de- velopment, etc. We would thus obtain four different lexical layers in specialized texts, as shown in Figure 1. In given applications (such as terminology resource com- pilation for which the method proposed in the paper is in- vestigated)2, identifying items that belong to one layer or the other can be quite difficult. For example, when working with a general environment corpus (such as PANACEA3 that covers a wide range of topics), some topic specific ter- minology might be difficult to spot since the …

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