three-way system of pasts with a contrast of hodiernal vs. hesternal vs. distant.
Systems with at least three degrees of past reference are widespread in Eastern
Bantu, e.g. Nyamwezi (Maganga & Schadeberg 1992: 103), Gogo (Cordell
1941), Sukuma (Batibo 1985; Olson 1964), and Rangi (Oliver Stegen, p.c.).
Cushitic languages typically express only aspect and have no morphological
tense system. In spite of this genetic predisposition, all the modern West Rift
languages have developed tense systems with two pasts. A twofold past system
has been be reconstructed for Proto-West Rift (Kießling 2002a: 375ff., 413f.),
operating on the basis of a contrast of preverbal clitics in for persistive vs. gaa for
past. The ultimate origin of both morphemes is unclear; the tendency of past gaa
to reduce to aa in most of the modern West Rift languages is considered to be a
convergent development to conform to the Bantu past prefixes a-anda
´
-in
neighboring languages such as Nyaturu (Olson 1964;Nurse2000a). Proto-
Northern West Rift (Iraqw, Gorwaa, Alagwa) has even developed another past
by fusion of (i)n plus (g)aa to naa, closely paralleled by Nyaturu verbal proclitic
na
´
a for far past, but their position in the preverbal clitic complex does not
correspond. The development of two pasts in Proto-West Rift is considered a
Bantu substrate, and the subsequent innovation of the naa past in Proto-Northern
West Rift is an indication of prevailing Bantu impact.
Datooga has two tenses with a past-reference component, i.e. perfect and
persistive, both of which do not seem to be inherited from Proto-Southern
Nilotic (Rottland 1982: 177ff .). The perfect tense is marked by the allomorphs
n-, si-, and i- (origin unclear), whereas the persistive in gudu can be traced back
internally to a periphrastic construction with the verb ‘finish.’ Here too we
have to assume Bantu structural influence due to a Bantu substrate.
In addition to tense distinctions in the past, various languages of our contact
zone also introduced a tense system that has at least one non-analytic future
tense. Proliferation of morphologically distinct future tenses is also a feature
typical of many Bantu languages. Some Bantu lang uages accomm odate up to
four different future tenses, e.g. Gogo (Cordell 1941: 50). In the contact zone,
Sukuma and Nyamwezi have three futures, Kimbu has two, Nilyamba, Nya-
turu, Rangi, and Mbugwe have one. These numbers include morphologically
discrete futures, they do not include present tenses functioning as futures.
Cushitic languages do not normally mark tense at the morphological level.
No tense marker, let alone future, has been reconstructed for Cushitic. Proto-
West Rift also had no morphological marker for future reference, but among
the modern West Rift languages Burunge stands out as havi ng innovated three
futures marked by the preverbal clitics aa for near future, oo for prospective,
and maa for distant future. It is not only the categories that must be considered
Bantu influence here, but also the form of the prospective morpheme at least,
since it is closely paralleled by the future *o- of the Ruvu Bantu group (Gogo,
Luguru, Zaramo, and others; see Nurse & Philippson 1975: 9). There is a
Roland Kießling et al.212