Universal Words and their relationship to Multilinguality, Wordnet and Multiwords

In this article we address issues concerning construction of lexicon in the context of sentential knowledge representation in Universal Networking Language (UNL), an interlingua proposed in 1996 for machine translation. Lexical knowledge in UNL is in the form of Universal Words (UWs) which are concepts expressed by mostly English words disambiguated and stored in the universal words repository. The UW dictionary is universal in the sense that it aims to store all concepts of all languages of all times. After many incarnations of UW dictionaries were built at many places of the world, the UW dictionary that is based on the content and structure of English wordnet seems to have found unanimous acceptance in the UNL community. We point that some of the concerns that challenge the wordnet building activity, challenge the construction of the UW dictionary too. These concerns are multilinguality and multiwords. We discuss possible solutions to these challenges, noting on the way that challenges to UW dictionary construction arise from the ambition of UWs repository to be universal.