Natural Languages as Collections of Resources

We propose a shift in perspective from the view of natural languages as formal languages to natural languages as a collection of resources for constructing local languages for use in particular situations. This is suggested by our experience constructing natural language grammars for particular applications using the Grammatical Framework. It points to a research programme investigating how such resources play a role in linguistic innovation by agents constructing situation-specific local languages and how they can be made dynamic, modified by the linguistic agent’s exposure to innovative linguistic data. 1 Natural languages and formal languages The view of natural languages as formal languages played a significant role in the development of linguistics in the second half of the twentieth century. The view of languages as sets of strings underlay the early development of generative transformational grammar. The following famous quotation from Montague’s (1974) ‘Universal Grammar’ represents a cornerstone of work on formal semantics since the seventies: ∗This work was supported by Vetenskapsradet project 2005-4211 Library-based Grammar Engineering , http://www.cs. chalmers.se/~aarne/GF/doc/vr.html. There is in my opinion no important theoretical difference between natural languages and the artificial languages of logicians; indeed I consider it possible to comprehend the syntax and semantics of both kinds of languages within a single natural and mathematically precise theory. Formal semantics involves the treatment of interpreted formal languages which may be regarded as sets of pairs of string and meanings. Chomsky (1980) and in other work makes clear that he does not regard natural languages as formal languages, or that at least to regard them in terms of string sets is at best missing the point of linguistic theory and at worst dealing with an incoherent notion. In his view, speakers of a natural language have acquired particular individual instantiations of universal principles. It is the nature of the principles and the parameters involved in instantiating them which are of interest for linguistic theory, not the nature of a string set corresponding to external public language, which may not be consistent since each speaker will have acquired their own individual grammar. While the view we propose in this paper is somewhat different to Chomsky’s, we share with him a focus on the formal characterization of the resources available to a speaker of a natural language, rather than a characterization of a set of strings (or string-meaning pairs) which are to be regarded as grammatical in the language. In this paper we will first discuss the advantages and disadvantages of regarding natural languages as formal languages (section 1.1). We will then (section 1.2) propose a view on which natural languages are rather to be regarded as collections of resources, a toolbox which can be used for constructing languages in the formal sense. This view arose from work on the Grammatical Framework, an implemented system for the construction of small application grammars based on general resources for natural languages and we will give a brief characterization of the system in section 2. Finally, we will speculate on how our view could be extended to accommodate linguistic innovation (section 3). 1.1 Are natural languages formal languages? The view of natural languages as formal languages was a tremendously productive abstraction which enabled us to apply twentieth century logical techniques to the characterization of human linguistic ability. Without it we would be able to say very little that is mathematically precise about the structure of language and its interpretation. It has provided great insight into the nature of language and has