\textit{A little bit of bella pianura}: Detecting Code-Mixing in Historical English Travel Writing
Authors: Rachele Sprugnoli, Sara Tonelli, Giovanni Moretti, Stefano Menini (Fondazione Bruno Kessler, Università di Trento, 2017)
Topic: Lexical and Semantic Resources and Analysis

Abstract
Code-mixing is the alternation between two or more languages in the same text. This phenomenon is very relevant in the travel domain, since it can provide new insight in the way foreign cultures are perceived and described to the readers. In this paper, we analyse English-Italian code-mixing in historical English travel writings about Italy. We retrain and compare two existing systems for the automatic detection of code-mixing, and analyse the semantic categories mostly connected to Italian. Besides, we release the domain corpus used in our experiments and the output of the extraction.

Introduction
Code-mixing is the alternation between two or more languages that can occur between sentences (inter-sentential), within the same utterance (intra-sentential), or even inside a single token (mixing of morphemes). This phenomenon has been widely studied from the linguistic, psycholinguistic, and sociolinguistic point of view AUTHOR but there is no consensus on the terminology to be adopted. In this paper code-mixing is used as an umbrella term to indicate a manifestation of language contact subsuming other expressions such as code-switching, languaging, borrowing, language crossing AUTHOR.\\ \indent Code-mixing characterizes communication of post-colonial, migrant and multilingual communities AUTHOR and it emerges in different types of documents, for example parliamentary debates, interviews and social media posts AUTHOR. Travel writings (e.g. guidebooks, travelogues, diaries, blogs, travel articles in magazines) are affected as well by this phenomenon that has been studied in particular by analyzing small corpora of contemporary tourism discourse through manual inspection AUTHOR. Even if code-mixing occurs in less than 1% of the cases AUTHOR, it has several important functions in the travel domain: it gives a ``linguistic sense of place'' AUTHOR, it adds authenticity to a narration, it provides translation of cultural-specific words and it is a mean to define social identity (``us'' tourists versus ``they'' locals) AUTHOR.\\ \indent In this work, we investigate the phenomenon of code-mixing in travel writings, but differently from previous works we shift the focus of analysis from contemporary to historical data and from manual to automatic information extraction. As for the first point, we present a corpus of more than 3.5 millions words of English travel writings published between the end of the XIX Century and the beginning of the XX Century, which we have retrieved from freely available sources and we release in a cleaned format. As for automatic information extraction, we retrain two state-of-the-art tools to identify English-Italian code-mixing and evaluate them on a sample of our dataset. We further launch the best system on the whole dataset and then we perform a semi-automatic refinement of the automatic annotation. The corpus, the training and test data and the outcome of the extraction are available online}.

Conclusion
In this work, we presented the first automated analysis of code-mixing in historical travel writings. In particular, we focus on English documents about Italy, and we compare guidebooks and travel narratives, analysing the semantic categories mostly related to code-mixing. In the future, we plan to investigate how code-mixing phenomena relate to content types in travel writings AUTHOR. Besides, we are planning to implement an algorithm to automatically link code-mixing quotations to their original source text. Finally, we would like to extend our experiments to recognise code-mixing in multiple languages, and compare the semantic domains specific to each language.