The derivatives of Barth's Law in the light of modern Arabic dialects

In 1894, Jacob Barth proposed that the preformative conjugation in some of the Semitic languages goes back to a – generally bygone – inverse correlation between the thematic vowel of the stem and that of the conjugational prefix. Evidence for such a distribution is well attested in all branches of Central Semitic, yet it remains disputed whether it should be reconstructed for Proto-Semitic as well. This paper makes use of new data from a living Semitic variety, namely the Arabic dialect of Ḥugariyyah in the south of Yemen, where the pattern observed by Barth is still operative. We examine the interaction of the conjugational prefixes with the dialectal future tense marker š(a)-, and point to cases where the inverse correlation is violated. We outline a sequential development, starting with a phonetically-driven re-distribution of the preformative vowels, and followed by their reanalysis as integral to the prefix. We then propose that comparable developments may have taken place in other Semitic varieties, predominantly Akkadian, and thus view the Akkadian preformative conjugation as a derivative of a former inverse correlation, as reconstructed by Barth.