Linguists and archaeologists offer complementary view- points on human behaviour and culture in past African communities. While historical-comparative linguistics commonly deals with the immaterial traces of the past in Africa’s present-day languages, archaeology unearths the material vestiges of ancient cultures. Even if both sciences share similar core concepts, their methods, data and interpretive frameworks are profoundly different. Explaining some basic principles of historical-compar- ative linguistics as applied to the Bantu languages and debunking some common misconceptions are the central aims of this contribution. Due to space constraints, no detailed bibliographic references are provided through- out the text (see my earlier publications for extensive bibliographies). 2 Some essential readings for non-spe- cialists are listed at the end of this chapter. I. DIACHRONIC LINGUISTICS ON THE BASIS OF SYNCHRONIC DATA Ideally speaking, historical linguistics is the study of distinct historical stages in the evolution of one single language or language family. This is the case in Ro- mance, for instance, where the development of Latin into its multiple daughter languages can be empirically reconstructed. In Africa, examining language variation through time on the basis of diachronic language data is hardly ever possible, due to the lack of written docu- ments. The case of Kikongo, whose historical record starts in the early 17th century, is exceptional, and even not equalled by Kiswahili whose oldest surviving texts do not date further back than the mid-18th century. For most other Central African languages, written docu- ments become at best available from the late 19th cen- tury onwards. Even today, there are still many undocu- mented languages, several of which are on the verge of extinction. Historical linguistics in Africa thus usually consists in the comparative study of historically-related languages. This up-stream approach, also known as 1 BantUGent - UGent Centre for Bantu Studies, Department of Languages and Cultures, Ghent University, Belgium. 2 http://research.lw.ugent.be/en/koen.bostoen ‘historical-comparative linguistics’, starts from extant languages and tries to reconstruct their evolution from ancestral stages through the study of current-day varia- tion. Such inter-language variation can be phonological, morphological, syntactic, semantic or lexical. In the case of Bantu, the hypothetical common ances- tor language reconstructed on the basis of similarities observed between languages known mainly from the 19th century onwards is commonly called Proto-Bantu. This proto-language is assumed to be the best possible relection of the ancestor language that was supposedly spoken some 4,000 to 5,000 years ago in the area from where Bantu languages started to spread through Central Africa and beyond. Bantu linguists agree to situate this homeland in the so-called Grassields region of Cam- eroon, not far from the country’s border with Nigeria. This zone displays the highest linguistic diversity (which means that parent languages had suficient time to di- verge locally) and is close to the area where the Benue- Congo relatives of Bantu languages are spoken. II. REFERENTIAL VS. HISTORICAL OR GENEA- LOGICAL CLASSIFICATIONS The best-known Bantu classiication is no doubt Mal- colm Guthrie’s. In 1948, Guthrie subdivided the Bantu languages in 16 different zones labelled A, B, C, D, E, F, G, H, K, L, M, N, P, R, S and T, which he reduced to 15 in 1971 by merging the last two to one zone. Each zone is further subdivided into language groups, indicated by a decimal number, in which individual languages are indicated by a unit. Lowercase letters following certain units refer to dialects of a same language, e.g. Ciluba (L31a) and Lulua (L31b). In contrast to what is often believed, Guthrie’s classiication is strictly referential and was never meant to be historical: Guthrie did not rely on the ‘Comparative Method’ (which is the core ap- proach of historical-comparative linguistics) or ‘shared innovations’, its basic principle for historical subgroup- ing. Shared innovations are lexical, phonological or grammatical changes that took place only once in some ancestor language from which its daughter languages in- herited it and which are therefore indicative of the closer HISTORICAL LINGUISTICS Koen Bostoen 1 K. Bostoen. Historical Linguistics 257