The Annotation of Liber Abbaci, a Domain-Specific Latin Resource
Authors: Francesco Grotto, Rachele Sprugnoli, Margherita Fantoli, Maria Simi, Flavio Massimiliano Cecchini, Marco Carlo Passarotti (Scuola Normale Superiore, Università Cattolica del Sacro Cuore, KU Leuven, Università di Pisa, 2021)
Topic: Latin Resources

Abstract
The Liber Abbaci (13th century) is a milestone in the history of mathematics and accounting. Due to the late stage of Latin, its features and its very specialized content, it also represents a unique resource for scholars working on Latin corpora. In this paper we present the annotation and linking work carried out in the frame of the project Fibonacci 1202-2021. A gold-standard lemmatization and part-of-speech tagging allow us to elaborate some first observations on the linguistic and historical features of the text, and to link the text to the Lila Knowledge Base, that has as its goal to make distributed linguistic resources for Latin interoperable by following the principles of the Linked Data paradigm. Starting from this specific case, we discuss the importance of annotating and linking scientific and technical texts, in order to (a) compare and search them together with other (non-technical) Latin texts (b) train, apply and evaluate nlp resources on a non-standard variety of Latin. The paper also describes the fruitful interaction and coordination between nlp experts and traditional Latin scholars on a project requiring a large range of expertise.

Introduction
Latin texts have a wide diachronic and diatopic extension that corresponds to a similarly large diversity of the textual genres they represent. Besides literary ones, a huge amount of Latin texts of several different genres can be found spread all over Europe and beyond. An important textual genre is represented by scientific treaties, which in many cases are interesting not only for their contents, but also because of the technical terminology they feature.   This is precisely the case for the Liber Abbaci `the book of the abacus' by Leonardo of Pisa (also known as Fibonacci). Written in the very first years of the 1200s, it is a book on arithmetic promoting a style of calculation based on Arabic numerals without aid of an abacus. Fibonacci 1202-2021 is a project financed by the Tuscany Region and involving the University of Pisa and the Galilei Museum in Florence, following the publication of a critical edition of the Liber Abbaci by Enrico Giusti <cit.>. The goal of the project is to produce an enhanced digital edition of this work by leveraging advanced publishing tools and investigating the use of computational linguistics techniques in order to uncover the wealth of linguistic, scientific and historical information contained in the book.  Besides its scientific interest, the Liber Abbaci features a very peculiar lexicon, not often represented in the currently available (linguistically annotated) corpora for Latin. In order to fill this gap, in the context of the project Fibonacci 1202-2021 we have started performing the linguistic annotation of the Liber Abbaci, beginning from part-of-speech (PoS) tagging and lemmatization of a specific chapter of the book, chosen for its linguistic and historical interest. The dataset is freely available online[ <http://dialogo.di.unipi.it/LiberAbbaci>].  This paper describes the process of annotation of the Liber Abbaci and two applications of its results, namely (a) the evaluation of a number of trained models for PoS tagging and lemmatization for Latin in out-of-domain fashion and (b) the interlinking of the annotated chapter with other linguistic resources for Latin through the Lila Knowledge Base (KB)[<https://lila-erc.eu>].

Conclusion
This paper describes the annotation of one chapter of the Liber Abbaci by Fibonacci, and reports on the linguistic peculiarities of this text and the ensuing challenges. The results of existing UDPipe models in lemmatization and tagging show low accuracy and f1 scores when compared to the state of the art for these tasks in the recent EvaLatin 2020 evaluation campaign. This, on the one hand, can be attributed to the characteristics of the genre of Fibonacci's texts, which are representative of scientific Medieval Latin texts, and on the other hand can be explained with the different choices in annotation style of Latin treebanks released under the ud project. Substantial improvements can be expected with models trained on new releases of Latin treebanks which have already undertaken the effort of resolving annotation discrepancies and of making the annotation style across treebanks more homogeneous. Further improvements will however require new annotated chapters and experiments in domain adaptation, which are scheduled as future work.