In this paper, we describe the findings of the SIGMORPHON 2020 shared task on unsupervised morphological paradigm completion (SIGMORPHON 2020 Task 2), a novel task in the field of inflectional morphology. Participants were asked to submit systems which take raw text and a list of lemmas as input, and output all inflected forms, i.e., the entire morphological paradigm, of each lemma. In order to simulate a realistic use case, we first released data for 5 development languages. However, systems were officially evaluated on 9 surprise languages, which were only revealed a few days before the submission deadline. We provided a modular baseline system, which is a pipeline of 4 components. 3 teams submitted a total of 7 systems, but, surprisingly, none of the submitted systems was able to improve over the baseline on average over all 9 test languages. Only on 3 languages did a submitted system obtain the best results. This shows that unsupervised morphological paradigm completion is still largely unsolved. We present an analysis here, so that this shared task will ground further research on the topic.
CoNLL-SIGMORPHON 2017 Shared Task: Universal Morphological Reinflection in 52 Languages
Johns Hopkins University（约翰斯·霍普金斯大学）；University of Zurich（苏黎世大学）；University of Melbourne（墨尔本大学）；Google（谷歌）；Indiana University（印第安纳大学）；University of Colorado（科罗拉多大学）
The CoNLL--SIGMORPHON 2018 Shared Task: Universal Morphological Reinflection
Johns Hopkins University（约翰霍普金斯大学）；University of Zurich（苏黎世大学）；University of Melbourne（墨尔本大学）；NYU（纽约大学）；University of Colorado（科罗拉多大学）；University of Helsinki（赫尔辛基大学）
The SIGMORPHON 2019 Shared Task: Morphological Analysis in Context and Cross-Lingual Transfer for Inflection
Johns Hopkins University（约翰斯·霍普金斯大学）；University of Melbourne（墨尔本大学）；Allen Institute for AI（艾伦人工智能研究所）；Google（谷歌）；University of Helsinki（赫尔辛基大学）；Stony Brook University（石溪大学）；University of Colorado（科罗拉多大学）
SIGMORPHON 2020 Shared Task 0: Typologically Diverse Morphological Inflection
University of Melbourne（墨尔本大学）；University of Cambridge（剑桥大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Higher School of Economics（高等经济学院）；Moscow State University（莫斯科国立大学）；Karelian Research Centre（卡累利阿研究中心）；Indiana University（印第安纳大学）；Google AI（谷歌人工智能）；University of British Columbia（不列颠哥伦比亚大学）；Facebook AI Research（Facebook人工智能研究院）；Carnegie Mellon University（卡内基梅隆大学）；University of Louisville（路易斯维尔大学）；University of York（约克大学）；ETH Zürich（苏黎世联邦理工学院）；University of Colorado Boulder（科罗拉多大学博尔德分校）
