Retrieving relatives from historical data

Variation and change in relativization strategies has been well documented (e. g. Ball 1996: 46, Biber and Clark 2002, Biber, Johansson, Leech, Conrad and Finegan 1999, Johansson 2006, Lehmann 2002). Certain types of relative clause, namely that-relatives and zero relatives, were difficult to retrieve from plain-text corpora. Studies therefore either relied on manual extraction of data or a subset of possible relativization strategies. In some text types, however, the zero relative is an important member of the class of possible relativizers. Recent advances in syntactic annotation should have made that-relatives and zero relatives more accessible to automatic retrieval. In this article, we test precision and recall of searches on a modest-sized corpus, i.e. scientific texts from ARCHER (A Representative Corpus of Historical English Registers), as a preliminary to future work on the large corpora which are increasingly becoming available. The parser retrieved some false positives and at the same time missed some relevant data. We discuss structural reasons for both kinds of shortcoming as well as the possibilities and limitations of parser adaptation.