Cross-language projection of multilayer semantic annotation in the NewsReader Wikinews Italian Corpus (WItaC)
Authors: Manuela Speranza, Anne-Lyse Minard (Fondazione Bruno Kessler, 2015)
Topic: Lexical and Semantic Resources and Analysis

Abstract
In this paper we present the annotation of events, entities, relations and coreference chains performed on Italian translations of English annotated texts. As manual annotation is a very expensive and time-consuming task, we devised a cross-lingual projection procedure based on the manual alignment of annotated elements.

Introduction
The NewsReader Wikinews Italian Corpus (WItaC) is a new Italian annotated corpus consisting of English articles taken from Wikinews) is a collection of multilingual online news articles written collaboratively in a wiki-like manner.} and translated into Italian by professional translators. The English corpus was created and annotated manually within the NewsReader project,} whose goal is to build a multilingual system able to reconstruct storylines across news articles in order to provide policy and decision makers with an overview of what happened, to whom, when, and where. Semantic annotations in the NewsReader English Wikinews corpus span over multiple levels, including both intra-document annotation (entities, events, temporal information, semantic roles, and event and entity coreference) and cross-document annotation (event and entity coreference). As manual annotation is a very expensive and time-consuming task, we devised a procedure to automatically project the annotations already available in the English texts onto the Italian translations, based on the manual alignment of the annotated elements in the two languages. The English corpus, taken directly from Wikinews, together with WItaC, being its translation, ensures access to non-copyrighted articles for the evaluation of the NewsReader system and the possibility of comparing results in the two languages at a finegrained level. WItaC aims at being a reference for the evaluation of storylines reconstruction, a task requiring several subtasks, e.g. semantic role labeling (SRL) and event coreference. In addition, it is part of a cross-lingually annotated corpus, thus enabling for experiments across different languages. The remainder of this article is organized as follows. We review related work in Section~sec:soa. In Section~sec:annotEnglish we present the annotations available in the English corpus used as the source for the projection of the annotation. In Section 2 we detail some adaptations of the guidelines specific for Italian. In Sections3 and 4 we describe the annotation process and the resulting WItaC corpus. Finally, we conclude presenting some future work.

Conclusion
We have presented WItaC, a new corpus consisting of Italian translations of English texts annotated using a cross-lingual projection method. We acknowledge some influence of English in the translated texts (for instance, we noticed an above-average occurrence of noun modifiers, as in “dipendenti Airbus”) and in the annotation (for instance, annotators might have been influenced by English in the identification of light verb constructions in the Italian corpus). On the other hand, this method enabled us not only to considerably reduce the annotation effort, but also to add a new cross-lingual level to the NewsReader corpus; in fact, we now have two annotated corpora, in English and Italian, in which entity and event instances (in total, over 1,600) are shared. In the short-term we plan to manually revise the projected relations and add the language-specific attributes. We also plan to use the corpus as a dataset for a shared evaluation task and afterwards we will make it freely available from the website of the HLT-NLP group at FBK6 and from the website of the NewsReader project.