Heterosemy and the grammar-lexicon trade-off

A fundamental task for the grammarian is to determine what will be listed in the lexicon, and what will be derived from this list by productive rules specified in the grammar. The balance of information between grammar and lexicon becomes – in principle – an economical trade-off. While a grammarian can theoretically make as many detailed distinctions as he or she likes, the description should capture useful generalisations in an accessible way. Ideally this will reflect natural relationships at higher levels within the linguistic system being described. The need to balance parsimony, accuracy and comprehensiveness, readability, and intuitive faithfulness to the genius of a language is what makes grammar-writing as much an art as it is a technical craft. This tension is exemplified by the problem to be discussed in this chapter, namely: How should the grammarian treat a morpheme which apparently has membership in more than one grammatical class?