It is appropriate to devote some attention to the emergence and development of markers of definiteness, because a great deal has been written on this topic, both from the point of view of general historical linguistics and in work on particular languages or language families. Indeed, in the course of the present study, I have repeatedly made reference to the diachronic sources of articles in other, typically demonstrative, elements. It may be too much to say that this area of morphosyntax is more prone to historical change than others, but research indicates that it is possible to trace quite radical shifts acecting definiteness and determiners, sometimes over relatively short time spans. In this chapter I will examine three aspects of this issue: first, the acquisition of a syntactic category of definiteness by languages previously lacking it; second, the emergence of articles from other, substantive, determiners; third, the subsequent development of articles and definiteness.

The emergence of functional structure

Until recently, most research on the appearance of definiteness marking in languages which had previously lacked it concentrated on the process of semantic weakening whereby a demonstrative, or other determiner, became a definite article. But the development in the last few years of the theory of functional categories, including the DP analysis of the noun phrase, has made it possible to look at the question in new ways. It is assumed that languages vary in what functional projections they have (so that, for example, a language with no number marking can be taken to lack NumP), and the absence of DP in a given language should have the consequence, on the standard DP hypothesis as outlined in 8.2, that this language has no class of determiner.