Translation Equivalence and Synonymy: Preserving the Synsets in Cross-lingual Wordnets (2018)

Abstract: The Princeton WordNet for English was founded on the synonymy relation, and multilingual wordnets are primarily developed by creating equivalent synsets in the respective languages. The process would often rely on translation equivalents obtained from existing bilingual dictionaries. This paper discusses some observations from the Chinese Open Wordnet, especially from the adjective subnet, to illuminate potential blind spots of the approach which may lead to the formation of non-synsets in the new wordnet. With cross-linguistic differences duly taken into account, alternative representations of cross-lingual lexical relations are proposed to better capture the language-specific properties. It is also suggested that such cross-lingual representation encompassing the cognitive as well as linguistic aspects of meaning is beneficial for a lexical resource to be used by both humans and computers.

## introduction the development of multilingual wordnets has been accomplished mostly by starting with the princeton wordnet for english @xcite and supplying translation equivalents from another language to individual concepts represented by the synsets. when conceptual gaps are identified, they may be handled by the addition or omission of synsets in the new wordnet. while the approach has the merit of good coverage, reliance on translation equivalents may be at the expense of forming non-synsets in the target language wordnet, for which great caution has to be exerted. past experience from building multilingual wordnets has observed various difficulties, mostly arising from cross-linguistic differences in lexicalisation, conceptual space and sense distinction (e.g. @xcite . this paper discusses further observations from the chinese open wordnet @xcite , which added new translations from authoritative bilingual dictionaries as a means to increase coverage, to show that translation equivalents need to be very carefully screened to avoid some potential and easily overlooked pitfalls. while a good coverage is appreciated, especially with a view to use the wordnets in a variety of computational and human language applications, it is suggested that alternative representations including additional relational pointers be used to accommodate cross-linguistic differences without disturbing the basic infrastructure of wordnet, in particular its basic definition of synsets. the rest of this paper is organised as follows: section 2 reviews the theoretical basis of the princeton wordnet (pwn) and the construction of the chinese open wordnet (cow). attention will be focused on adjectives. section 3 presents some observations from cow in terms of its resulting synsets in the adjective subnet. section 4 discusses the cross-lingual aspects and proposes alternative ways for representing the lexical semantic relations, followed by a conclusion in section 5. ## synsets in cow the chinese open wordnet (cow) 3 consists of 42,312 synsets (nouns 65.9%, verbs 12.2%, adjectives 20.2%, adverbs 1.7%) with 80,009 lexical items (nouns 57.9%, verbs 16.7%, adjectives 22.9%, adverbs 2.5%). the following discussion covers the three major word classes, namely nouns, verbs and adjectives, with focus on adjectives, and adverbs are excluded. ## handling extra-synset information while it is intrinsically more difficult to define the synsets and concepts represented by adjectives due to their polysemy, even in pwn, the adjective database also reveals important conceptual and lexical gaps across languages. multilingual wordnets, in this regard, would provide useful resources for language learning and translation, by humans and machines alike. it has been shown from the above discussion that apart from paying attention to cultural and linguistic differences across languages, building wordnets in other languages based on translation equivalents from bilingual dictionaries does not necessarily result in equivalent and valid synsets. this issue is a salient one, especially for languages with very different morphological properties and word formation mechanisms from english. for instance, while new words can easily be formed by inflectional and derivational morphology in english, the meaning carried by the additional morphemes may often be straightforwardly rendered with an extra word in chinese, such as un-x to 不x (e.g. unhappy 不快乐 bù kuàilè) and x-able to 可x (e.g. respectable 可尊敬 kě zūnjìng) 5 . realising the importance and potential use of the multiple forms and renditions of a given meaning in chinese, or other languages which are similarly distant from english, it would therefore be 5 sometimes disyllabic words as a more lexicalised form are available, e.g. 不快 bùkuài or 不乐 bùlè for "unhappy" and 可敬 kějìng for "respectable", although they might be considered leaning toward classical chinese. ## conclusion this paper has thus raised the issue of preserving the synonymy relation holding in synsets as the basic building blocks for wordnets in other languages, while taking advantage of the translation equivalents from other lexical resources as a starting point. examples from chinese were highlighted to illustrate how cross-linguistic differences especially in morphology and word formation may result in non-synsets in the process of building wordnet in a target language. it has been shown that the adjective database is particularly prone to the problem, especially for the relatively "general" concepts expressed by adjectives which can be used to describe many different entities and qualify a wide range of properties. to avoid nonsynsets, it is thus suggested that partial equivalence be handled in a target wordnet by connecting the context-dependent equivalents to the basic synset with extra relational pointers. although the alternative representation may not make any significant difference as far as the coverage and actual usage of the resource is concerned, it is nevertheless fundamentally important to keep the theoretical foundation intact.