Tonal asymmetries between word classes and word shapes as a key to tonal reconstruction

International audienceMany Mande languages show important asymmetries in the tone patterns available for words of different classes and word shapes. Such tonal asymmetries offer an invaluable window on the history of tone systems that have them. This paper takes Tura, a Southeastern Mande language spoken in Côte d’Ivoire, as an illustration of how tonal asymmetries can be fruitfully exploited for purposes of tonal reconstruction with some far-reaching implications for the tonal reconstruction of Mande as a whole.Tura uses the mora as the tone-bearing unit and has four tone levels: a̋ extra-high E (from the e of extra), á high H, à low L and ȁ extra-low G (from the g of grave accent). However, the full four tone level range is exploited only on bimoraic nominal stems and on monomoraic pronominal stems. Monomoraic CV nominal stems distinguish three tone levels, viz. E, H and G. Monomoraic CV postpositions and verbal stems are characterised by the smallest range of only two tone levels, viz. E and G for postpositions and E and H for verbal stems. I argue that CV verbal stems faithfully reflect the original two-level tone system with E < *H and H < *L, while the present L and G also both go back to *L. In monomoraic words of other word classes, the original two level tone system has been somewhat blurred by later independent developments and borrowings. An important property of Tura segmental phonology that is directly relevant for tonal reconstruction is that Tura strongly tends to faithfully preserve the weight of bimoraic stems. This makes it very unlikely that the current tone patterns of CV verbal stems could have resulted from simplification of tone sequences due to contraction of earlier bimoraic stems.Together with a number of other Southeastern Mande languages, Tura boasts some of the richest Mande tone systems in terms of tone levels. An important outcome of the proposed reconstruction is that even such exuberant tone systems as that of Tura (and even more exuberant ones of some of the neighbouring varieties of Dan) can be safely brought back to an earlier two-level tone system. Given that the same can also be argued for the tone systems of Western Mande languages which are usually much more modest (cf. Dwyer 1994 on Bobo), Proto Mande can be equally safely reconstructed with just two tone levels