Formatio formosa est. Building a Word Formation Lexicon for Latin
Authors: Eleonora Litta, Marco Carlo Passarotti, Chris Culy (Università Cattolica del Sacro Cuore, 2016)
Topic: Latin Resources

Abstract
This paper presents the steps undertaken for building a word formation lexicon for Latin. The types of word formation rules are discussed and the semi-automatic procedure to pair their input and output lexical items is evaluated. An on-line graphical query system to access the lexicon is described as well.

Introduction
In the area of Natural Language Processing (NLP), derivational morphology has always been neglected if compared to inflectional morphology, which plays a central role in fundamental annotation tasks like PoS tagging. Yet enhancing textual data with derivational morphology tagging promises to provide strong outcomes. First, it organises the lexicon at higher level than words, by building word formation based sets of lexical items sharing a common derivational ancestor. Secondly, derivational morphology acts like a kind of interface between morphology and semantics, since core semantic properties are shared at different extent by words built by a common word formation process. Lately, some lexical resources for derivational morphology have been made available. Among them are the lexical network for Czech DeriNet AUTHOR, the derivational lexicon for German DErivBASE (AUTHOR) and that for Italian derIvaTario (AUTHOR). Furthermore, stemming is a technique largely used for detecting word formation processes (AUTHOR), and language independent NLP tools were trained to extract derivation information from inflectional lexica (AUTHOR). On the Classical languages front, although the number of resources and NLP tools for Ancient Greek and Latin is now manifold and varied (ranging from digital libraries, treebanks and computational lexica to PoS taggers and parsers), no lexical resource for derivational morphology is available yet, where words are connected by word formation processes. The first steps towards building such a word formation lexicon for Latin were made by AUTHOR, who described a model for the semi-automatic extraction of word formation rules from the list of lemmas of Lexicon Totius Latinitatis by Forcellini (fifth edition; 1940) and the subsequent pairing of lexical entries and their derivational ancestor(s). The Word Formation Latin project has received funding from the EU Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Individual Fellowship to expand on these efforts and create a word formation lexicon (working as an NLP tool as well) for Latin. In this paper, we describe the steps undertaken to build such a lexicon. The paper is organised as follows. Section 2 presents the lexical basis supporting the lexicon; section 3 details the way the lexicon is built; section 4 describes how to access the data; section 5 concludes the paper and sketches the future work.

Conclusion
The building process of the word formation lexicon for Latin is ongoing. We still have to fully exploit the potential of querying the lexical basis of Lemlat to automatically detect candidates for WFRs. Furthermore, a substantial amount of manual work is needed to pick up morphotactically obscure formations, like those resulting from compounding. The word formation lexicon is meant to enhance Lemlat by providing its processing with word formation analysis of input data, thus building a wide lexical resource and NLP tool for Latin morphology, which will be made available through CLARIN infrastructure.