Computational Linguistics is the longest-running publication devoted exclusively to the computational and mathematical properties of language and the design and analysis of natural language processing systems. This highly regarded quarterly offers university and industry linguists, computational linguists, artificial intelligence and machine learning investigators, cognitive scientists, speech specialists, and philosophers the latest information about the computational aspects of all the facets of research on language. Computational Linguistics is published by the MIT Press on behalf of The Association for Computational Linguistics. Beginning with the March 2017 issue of Computational Linguistics, all articles are published under a CC BY-NC-ND 4.0 license. For more information on allowed uses, please view the CC license. Copies of articles identified as "Free" may be downloaded at no charge. You may share the exact file with colleagues on an ad hoc basis, and may reproduce the exact file for non-profit educational use provided that no charge is made for doing so other than as necessary to cover the cost of reproduction. All copyright and other rights are reserved, however, and no other use may be made of the file or its contents except as permitted under the doctrine of fair use or as expressly permitted in writing by the MIT Press.