Spirantization and the 7-to-5 Vowel Merger in Bantu

. Many Bantu languages have the balanced seven-vowel system i i e a c u u. It is the system that one would, on internal evidence, reconstruct for proto-Bantu. Many other Bantu languages have a reduced five-vowel system i e a c u. The five-vowel systems are historically almost always the result of a merger of the two highest front and back vowels, respectively; i.e., the result of a merger of *i /*i and of *u/*u ("7>5"). Another widespread sound change occurring in Bantu is the one here called "Spirantization". It occurs in seven-vowel languages and affects obstruents in the environment preceding the high vowels i and u (not i and v). It typically creates strident fricatives (s, f...) not formerly present in the system. Some remarkable observations can be made concerning the historical co-occurrence of the two sound shifts. Spirantization and 7>5: (i) No language has undergone 7>5 but not Spirantization; (ii) Only few languages have undergone Spirantization but not 7>5. (iii) In languages which have undergone both sound shifts, Spirantization always preceded 7>5. In this contribution I try to "explain" these patterns of co-occurrence without appeal to structuralist chain analyses. I consider both changes as being independently well motivated, and while admitting the possibility that the phonological system as such may favour or disfavour certain changes I argue that areal norm and areal spread are the major reasons for the widespread combined occurrence of Spirantization and 7>5, in that (apparent) order.