A proposal about the origin of the Indo-European locative plural

One of the most significant recent developments in the field of historical lin­ guistics has been the identification of what Fox (1995: 194) calls '"laws' oflanguage development"-a methodology "for determining which changes are more likely than others, and ... criteria for determining the overall direction of linguistic change." This methodology is largely an aspect of what has come to be known as "grammati­ calization theory," which, according to Heine (2003: 575), is really "neither a theory of language nor of language change; its goal is to describe grammaticalization, that is, the way grammatical forms arise and develop through space and time, and to explain why they are structured the way they are." The process of grammaticalization "is hypothesized to be essentially unidirectional" (Heine 2003: 575) and therefore potentially "offers an explanatory account of how and why grammatical categories arise and develop" (Heine 2003: 578). Such explanation serves as "a potentially powerful adjunct to the methods of reconstruction, especially on an internal basis" (Fox 1995: 206), since it leads the historical linguist to principled conclusions about the structural sources of both attested and comparatively reconstructed morpho­ syntactic patterns. In this brief paper I wish to apply one such '"law' of language development" to account for the origin of the traditionally reconstructed Inda-European locative plural suffixes *-si (Gk. -si) and *-su (Skt. -su, OCS -Xb) (cf. Szemerenyi 1996: 165). Like Fox (1995: 206), I acknowledge that the application of this methodology can be "speculative and controversial"; however, I offer my proposal as a reasonable possibility for developments within Indo-European