WikiWarsDE: A German corpus of narratives annotated with temporal expressions

Temporal information plays an important role in many natural language processing and understanding tasks. Therefore, the extraction and normalization of temporal expressions from documents are crucial preprocessing steps in these research areas, and several temporal taggers have been developed in the past. The quality of such temporal taggers is usually evaluated using annotated corpora as gold standards. However, existing annotated corpora only contain documents of the news domain, i.e., short documents with only few temporal expressions. A remarkable exception is the recently published corpus WikiWars, which is the first temporal annotated English corpus containing long narratives that are rich in temporal expressions. Following this example, in this paper, we describe the development and the characteristics of WikiWarsDE, a new temporal annotated corpus for German. Additionally, we present evaluation results of our temporal tagger HeidelTime on WikiWarsDE and compare them with results achieved on other corpora. Both, WikiWarsDE as well as our temporal tagger HeidelTime are publicly available