E nglish W ord N et 2019 – An Open-Source W ord N et for E nglish (2019)

Abstract: We describe the release of a new wordnet for English based on the Princeton WordNet, but now developed under an open-source model. In particular, this version of WordNet, which we call English WordNet 2019, which has been developed by multiple people around the world through GitHub, fixes many errors in previous wordnets for English. We give some details of the changes that have been made in this version and give some perspectives about likely future changes that will be made as this project continues to evolve.

## introduction wordnet @xcite is one of the most widely-used language resources in natural language processing and continues to find usage in a wide variety of applications including sentiment analysis @xcite , natural language generation @xcite and textual entailment @xcite . however, in the recent few years there has been only one update since version 3.0 was released in 2006, in spite of its wide use and the interest in the data. in the meantime, a number of other wordnet teams working with the wordnet data have proposed modifications or extensions to its latest release. these two facts have provided the chief motivation for our present initiative, namely developing an opensource wordnet for english on the basis of princeton wordnet (to be released under the name english wordnet 2019). in order to allow for meaningful comparisons of performance on tasks using wordnet as a component, it is important to maintain a single (or very few) wordnets as a standard and reference. one of the core issues preventing further development of the original wordnet model has been the question of how to ensure the resource maintains its quality. the princeton wordnet team has followed a model that requires an expert lexicographer to review and implement all changes. in this paper, we discuss the development of open english wordnet, which instead follows a methodology of quality assurance that is based on those typically used for open-source projects, especially those connected to the linux operating system. in particular, we can consider this to be an application of linus's law ("given enough eyeballs, all bugs are shallow") to the development of wordnet, similar to other open source orientated projects such as openwordnetpt @xcite and the recently announced global framenet project foot_0 . still, we will do our best to make new data or proposed changes verified by expert lexicographers or developers whenever possible. we have implemented this in terms of a new 'fork' of princeton wordnet, and have released a new version of wordnet that fixes many of (mostly trivial) errors, such as spelling mistakes, and thus improves the quality of the resource. we take inspiration from other forks such as the mari-adb fork of mysql and aim to make this a 'dropin' replacement for princeton wordnet. this is achieved by ensuring that that data is available in a wide range of formats, including those used by princeton to publish the resource and standards promoted by the global wordnet association so that existing projects can use these changes without updates to their workflows. in particular, we continue to follow the basic conception of princeton wordnet and do not introduce changes that would fundamentally affect the nature of the wordnet. instead, our focus for this release is on fixing more minor errors and for future releases we plan to extend this to principally adding new synsets and relations, using the existing structure as a guide. as an open-source project we expect that the community will create synsets that reflect their views, and that this may in the long run lead to more significant divergences from the princeton wordnet model, moreover, we also present a new website and project that allows the resources to be queried at http://en-word.net , which presents the most recent changes in a dynamic manner as they are updated on the github website. to indicate that this is a clearly new version of wordnet we have termed this version the 2019 edition of english wordnet and provide a clear and auditable list of changes that have been made such that it would be possible for the princeton wordnet to use these changes in any future versions they make. this paper is structured as follows: first, we will present some other efforts to extend the princeton wordnet for english and then we will describe the kinds of changes that we have made for this release. we will then provide a brief discussion of the open issues that will be handled in the next version and how they may be handled. we will then briefly describe the release and the implementation of the user interface. ## background princeton wordnet @xcite is the first wordnet for english, however it is not the only one that has been developed for this language. moreover, it has been the case that during the development of several wordnets for other languages signficant changes and/or additions were made to the underlying structure and content of the english section of the wordnet. in at least one case, namely the development of the polish wordnet, plwordnet, the additions to the underlying english wordnet have been so numerous that they were released as a new wordnet, enwordnet @xcite . these involved the addition of new lemmas (over 11k), lexical units (over 11k) and synsets (7.5k). the latter were linked to wordnet 3.1 synsets via hyponymy relation. still, no alterations to the original wordnet synsets or relations were made within this project. currently, enwordnet is only available as part of the plwordnet project and does not constitute a 'drop-in' replacement for princeton wordnet. some projects have attempted to expand prince-ton wordnet with new terminology in other directions, for example the colloquial wordnet project @xcite , has been working on adding new terms that are used in social media, and this is available using the same gwc formats @xcite as this work; a similar project called slangnet @xcite seems to be unavailable now. there have also been a number of attempts to extend wordnet in terms of the kinds of annotation that it contains, such as the addition of sentiment and emotion information @xcite or combining it with a upper-level ontology @xcite . another significant direction has been the automatic extension of wordnet and several projects have been published based on extending word-net with information from other resources, especially wiktionary and wikipedia. one of the most prominent of such resources is babelnet @xcite , which combines multiple methods using machine learning based methods, which have been shown to have a precision of up to 89.7%. a similar effort was carried out by the ukp group and led to the uby resource @xcite , who report similar levels of accuracy in the mapping. while such automatically constructed resources may be valuable for a large number of applications, they cannot replace wordnet for applications that require a gold standard lexicon or very high precision. further, many of these resources have taken wordnet as is, and have often repeated the same design and frequently copied many of the minor errors into their own resources. ## the open english wordnet project the open english wordnet project foot_1 takes the form of a single git repository, published on github, and consisting for the most part of a collection of xml files describing the synsets and lexical entries in the resource. these xml files represent each of the lexicographer file sections of the original resource and a simple script is provided to stitch them together into a single xml file. the xml files are compliant with the gwc lmf model @xcite foot_2 , which is itself based partially on the lmf model @xcite and in particular the wordnet (a.k.a kyoto) lmf variant @xcite . due to its basis on lmf, a particular challenge was that the entire wordnet should be represented as a single xml document. however, due to the relative verbosity of the lmf format, the final data ended up as 97 mb, exceeding the upload limits of github, so instead the single xml file was divided by lexicographer sections. even still, this creates several very large files (over 10 mb) and this has resulted in some challenges for those working on the project foot_3 , which may be solved by the adoption of a less verbose format. the model for contributing to this work is similar to that of other large open-source projects, where a small number of trusted developers are able to make changes to the code directly to the source of the wordnet, while submissions may be proposed by any user registered with github in two principal channel: issues any user may log an issue with the system, describing the changes that they would like to make to the wordnet, along with technical information including the identifier of the synset and the type of proposed change (e.g., 'merge synset'). issues are then assigned to a trusted developer and implemented by them. pull request technically-inclined users may make the changes directly to the xml and propose them for review by one of the trusted developers. this method generally leads to faster acceptance of changes. in both cases, changes are covered by contribution guidelines foot_4 , which also maintain the integrity of the project in terms of fostering an inclusive, kind, harassment-free, and cooperative community. currently, this combination of technical hurdles and clear guidelines has prevented any cases of politically motivated or otherwise inappropriate changes being proposed to the wordnet. in addition to the raw data itself, a number of scripts have been introduced that can be used with the model. these include a 'post-receive' hook that takes the most recent changes to the wordnet and immediately converts it into other formats including rdf based on ontolex-lemon @xcite as well as in the wndb formats used for previous versions of wordnet, allowing english wordnet to be a 'drop-in' replacement for princeton wordnet. furthermore, this update is used to populate the searchable frontend, which is available at http://en-word.net/ . ## scope of changes one of the first major class of errors that we attempted to fix were simple spelling errors that occur particularly in the definitions and the examples of the synsets. in most cases these were entirely obvious errors for example the following definition: this change in a few cases also affected the lemmas in the resource, for example the lemma 'poetic jstice' was corrected. in a few cases, there was uncertainty as the spelling variant was non-standard, for example in 3 cases the word 'moslem' was used as opposed to the 115 cases of the far more common variant 'muslim', so these were corrected to a single spelling form. a second major source of errors was that many examples did not use any lemmas from the synset and as such could not be considered examples of the synset. we used a simple edit distance based approach to identify 434 synsets for which this appeared to be an issue. of those we found that 341 represented a clear error that was easy to be fixed. for these various strategies were followed: a third major change was to introduce new synset members based on a previously calculated wordnet-wikipedia mapping @xcite . in particular, if this mapping, which has already been manually verified, linked to a page title that did not match the lemma, the page title was added as a new lemma to the synset. this was, as with all changes, manually verified in its entirety before the change was made. finally, the repository has been open to new suggestions of changes and there have been many suggestions already contributed about sporadic and various changes to the wordnet. a sample of these include: ## ambition our ambition for this project is to have annual releases and as such we detail some of the changes that we plan to make that would not fundamentally change the nature of the resource, and these changes will likely be the basis of the releases for the next couple of years. we then look into more significant extensions that would be planned for releases in the long-term. ## results for this release this release represents a mostly maintenance release where obvious errors have been fixed. in ## interface to english wordnet in addition to the development of a new resource, we have also developed a new interface to the resource, which is available at https: //en-word.net . this interface is developed using the latest web technologies including the use of angularjs 12 and the use of rocket 13 , a rust-based framework for web applications. this interface is also open-source and released on github 14 . this interface provides a fast and attractive interface (see figure 1 ) to the data and in addition, allows the data to be browsed as linked data using the rdf interface as provided by @xcite . in addition, clear links are provided to the github to encourage contributions and to the global wordnet association. ## conclusion in this paper, we have presented a new version of wordnet for english that has been developed as a fork of the princeton wordnet and in particular we describe the first release of this resource as a 'drop-in' replacement for the princeton word-net. as a main contribution, we have moved the development of english wordnet to an opensource framework, ensuring that the development of wordnet is not constrained by the funding situation at a single institute. instead, we commit to a yearly update cycle and welcome contributions from many directions. we believe that one of the most important challenges with this will be ensuring that wordnet can remain a gold standard resource for nlp applications. moreover, we note that as this resource has fixed over 3,500 errors in wordnet, the english wordnet 2019 release is naturally of higher quality than any previous princeton wordnet release.