GrETEL 1.0

GrETEL is a query engine in which linguists can use a natural language example as a starting point for searching a treebank with limited knowledge about tree representations and formal query languages. Instead of a formal search instruction, it takes a natural language example as input. This provides a convenient way for novice and non-technical users to use treebanks with a limited knowledge of the underlying syntax and formal query languages. By allowing linguists to search for constructions similar to the example they provide, it aims to bridge the gap between descriptive-theoretical and computational linguistics. The example-based query procedure consists of several steps. In the first step the user enters an example of the construction he/she is interested in. In the second step the example is returned in the form of a matrix, in which the user specifies which aspects of this example are essential for the construction under investigation. The third step provides an overview of the search instruction, i.e. the subpart of the parse tree that contains the elements relevant for the construction under investigation. This query tree is automatically converted in an XPath query which can be used for the actual treebank search. This query can be edited if desired. In the fourth step the query is executed on the selected corpus. The matching constructions are presented to the user as a list of sentences, which can be downloaded. The user can also click on the sentences in order to visualize the results as syntax trees. GrETEL enables search in the LASSY-SMALL and the CGN (Spoken Dutch Corpus) Treebanks (1 million tokens each). GrETEL was created by CLARIN Dutch Language Union in Flanders in the context of the CLARIN-NL / CLARIN Flanders cooperation project.