Areal typology and grammaticalization
To date, the theory of grammaticalization has been oriented towards typological and cognitive treatment of mechanisms of grammaticalization. The study of areal diffusion and grammaticalization has been rather neglected, in spite of its obvious relevance to the ways in which grammaticalization may happen and the reasons why it occurs in one way and not in another way.
Linguistic areas are defined in terms of shared structural features. Languages spoken within a linguistic area very often display a significant degree of structural isomorphism (see Sherzer 1973:760; Thomason and Kaufman 1988:96). Diffusion of grammatical processes (termed ‘indirect’ diffusion by Heath 1978) may or may not be accompanied by some degree of lexical diffusion or actual borrowings (‘direct’ diffusion: Heath 1978). Linguistic areas differ in the degree to which direct diffusion takes place. What is common to all of them is convergence of grammatical categories and the presence of calques (loan-translations). One would also expect processes of grammaticalization to operate in the same direction in genetically unrelated languages spoken within one linguistic area. Moreover, one might expect the diffusion of grammaticalization processes together with other grammatical categories within the same linguistic area. In depth studies of patterns of areal diffusion of grammaticalization, alongside typologically established universal tendencies and cognitive explanations, can provide us with the reasons why a language has chosen this or that grammaticalization path.
Tariana shares verb compounding and grammaticalization of compounded verbs with other languages spoken in the same area (East-Tucano and Makú), but not with closely related languages of the North Arawak family which do not belong to the Vaupés area. In contrast, the grammaticalization of serial verbs is shared with its North Arawak relatives.
The linguistic area to which Tariana belongs is characterized briefly in §3.2. Verb serialization and verb compounding in languages of the area other than Tariana are considered in §3.3. Further evidence in favour of an areally diffused, and not genetically inherited, character of verb compounding in Tariana is given in §3.4.
