Deletions and Node Reconstructions in a Dependency-Based Multilevel Annotation Scheme

The aim of the present contribution is to put under scrutiny the ways in which the so-called deletions of elements in the surface shape of the sentence are treated in syntactically annotated corpora and to attempt at a categorization of deletions within a multilevel annotation scheme. We explain first (Sect. 1) the motivations of our research into this matter and in Sect. 2 we briefly overview how deletions are treated in some of the advanced annotation schemes for different languages. The core of the paper is Sect. 3, which is devoted to the treatment of deletions and node reconstructions on the two syntactic levels of annotation of the annotation scheme of the Prague Dependency Treebank (PDT). After a short account of PDT relevant for the issue under discussion (Sect. 3.1) and of the treatment of deletions at the level of surface structure of sentences (Sect. 3.2), we concentrate on selected types of reconstructions of the deleted items on the underlying (tectogrammatical) level of PDT (Sect. 3.3). In Section 3.4 we present some statistical data that offer a stimulating and encouraging ground for further investigations, both for linguistic theory and annotation practice. The results and the advantages of the approach applied and further perspectives are summarized in Sect. 4. 1 Motivation and Specification of Deletions (Ellipsis) Deletion (ellipsis) in language is a long-standing hard problem for all types of theories of formal description of language, and, consequently, also for those who design annotation schemes for language corpora. As such, this phenomenon present in all languages deserves a special attention both from the theoretical viewpoint as well as with regard to empirical studies based on large annotated corpora. Our contribution is based on a dependency-based grammatical theory, on a multilevel treatment of language system and is supported by language data present in the Prague Dependency Treebank for Czech (PDT); when relevant, we also comment upon the English data of the deep-structure annotation of the Wall Street Journal. 1 A theoretically-oriented analysis of ellipsis from the point of view of dependency grammar is presented in Panevová, Mikulová and Hajičová, to be submitted for DepLing 2015.