Latvian and Lithuanian Named Entity Recognition with TildeNER

In this paper the author presents TildeNER ― an open source freely available named entity recognition toolkit and the first multi-class named entity recognition system for Latvian and Lithuanian languages. The system is built upon a supervised conditional random field classifier and features heuristic and statistical refinement methods that improve supervised classification, thus boosting the overall system's performance. The toolkit provides means for named entity recognition model bootstrapping, plaintext document and also pre-processed (morpho-syntactically tagged) tab-separated document named entity tagging and evaluation on test data. The paper presents the design of the system, describes the most important data formats and briefly discusses extension possibilities to different languages. It also gives evaluation on human annotated gold standard test corpora for Latvian and Lithuanian languages as well as comparative performance analysis to a state-of-the art English named entity recognition system using parallel and strongly comparable corpora. The author gives analysis of the Latvian and Lithuanian named entity tagged corpora annotation process and the created named entity annotated corpora.