E stonian W ordnet: Current State and Future Prospects (2018)

Abstract: This paper presents Estonian Wordnet (EstWN) with its latest developments. We are focusing on the time period of 2011–2017 because during this time EstWN project was supported by the National Programme for Estonian Language Technology (NPELT1). We describe which were the goals at the beginning of 2011 and what are the accomplishments today. This paper serves as a summarizing report about the progress of EstWN during this programme. While building EstWN we have been concentrating on the fact, that EstWN as a valuable Estonian resource would also be compatible in a common multilingual framework.

## estwn odyssey from ili1.5 to pwn3.0 and to cili since we wanted estwn to be linked to the global wordnet association repository with collaborative interlingual index (cili), the first step was to update the old ili1.5 to the latest pwn3.0 version. as said before, different wordnets are generally similar but still need some effort to combine in a common interoperable multilingual framework @xcite . as follows we describe our efforts and challenges of the cili-linking process from the wordnet builders point of view. estwn was connected to ili1.5 almost 20 years, and on 2017 we could finally update ili1.5 to pwn3.0 thanks to our new wordnet editing tool -wordnet workbench foot_0 . the first ili version (1.5) contained more than 90 000 concepts, yet it was often difficult to determine equal synonyms from estonian to english. ili1.5 missed suitable senses, especially regarding adjectives and adverbs. another problem was that a lot of definitions were missing from ili and it was complicated to decide the exact meaning of the ili synsets. pwn 3.0 is of course much richer with different concepts to choose from, so we started to correct english equivalents systematicallychanging other ili-relations into more precise equal synonym relation. in order to share the data with open multilingual wordnet project, we still have to link estwn's synsets to cili, since the reference to cili is the obligatory attribute of synset. at the moment in estwn 22 345 synsets have the external reference with relation type 'eq_synonym' to pwn 3.0 and thereby are mapped to cili. number of cili-links which are not linked with estwn is 95 314. this number includes also 7556 proper names, connected with pwn via instance-relation. thus other (approx 65 thousand) synsets require work in order to either find a relation with appropriate concept from cili or in the future to define a new concept with a new definition and propose them to cili. it is also widely known, that some mistakes are inevitable and the solution is the manual correction of errors. next, we describe the process of improving english part of estwn through the english equivalents. since it is complicated and unreasonable to check english equivalents from the first entry in estwn, we composed different types of lists foot_1 , which we considered to be problematic. from these lists different types of mistakes occurred, for example, 940 english synsets were connected to 1881 estonian synsets via the eq_synonym relation, which indicates that these synsets need to be either corrected or united. ## future plans the estwn project has most definitely achieved the initial goals of the project and at the end of this npelt program, there is an appropriate time to set new goals and plan future activities. estwn project has several quite challenging stages ahead: we continue to increase the size of estwn with a special focus on the quality. another direction is to find applications for estwnit has been proven for estwn, that via these applications it is possible to perform different types of quality checks. we have to look more into the topic of the compound words because estwn is missing some of the mostly used compounds. for compound extraction a corpus will be used, and compounds which occur more than 10 times in this corpus are considered as possible candidates as new concepts or senses. the new editing tool wordnet workbench enables us to create, change or delete semantic relations, so we can create (and rename) new semantic relations valid for estonian and adopt relations from other resources, for example, domain relation from pwn. also, we plan to integrate domain labels from wordnetdomains automatically; of course we have to validate if the domains initially created for english apply also in the context of estonian. summing up, we can say that estwn has reached a level where it can be used in several language technology applications and in research as a valuable language resource.