8.1 Causative 441In the more usual deverbal causatives, the argument structure and case
frame is carried over from the input verb, with the addition of a new object
NP representing the subject of the underlying verb. There is no limit to the
number of arguments such a causative can have. In particular, it can have two
direct object NPs. The only constraint is a morphological one, namely that two
object clitics may not be adjacent (they may both appear if separated by a
dative clitic). See §9.1.7 and §10.4.
A similar -s- prefix (arguably the same prefix) is also used in the formation
of instrumental nominals (§8.11).
A variant Caus prefix allomorph -svw-, arguably bimorphemic -s-vw-,
occurs in two stems (see below). I refer to this as a w-extension. One might
compare it to the now very rare y-extensions found in one frozen mediopassive
(-nvyufu- 'be compared', §8.3) and in one frozen instrumental nominal,
a-saeyor 'key' (§8.11). The rare w-extended Causative prefix is structurally
similar to the vastly more productive Passive -tvw- alongside the simpler
allomorph -t- (§8.2).
One -svw- causative is 'cause to be done', which is based on -vji> 'do' or,
more relevantly, 'be done, happen' (§7.3.2.14). The Caus, like other verbal
derivatives, shows doubling of the j. The Caus forms are PerfP -aesw-aejja-,
Imprt S3ww-3jj, LoImpfP -saw-asjja-, and VblN a-saww-sjj. The w is treated
morphophonologically like an intervening prefix, hence the Stem-Initial
Gemination to ww in Imprt and VblN. The extension can be "justified" here as
a method of bulking up the causative of this unusually light stem with just one
lexical C.
A similar -svw- occurs in causatives of -uyyu- 'leave' (§7.3.1.15). One
causative paradigm, from T-ka, is -svw-vyyu-, with PerfP -aesw-asyya-, Imprt
saww-ayy, LoImpfP -saw-aeyya-, and VblN a-ssww-ayy. Another T-ka
causative paradigm, this time with double causative prefixation, is
-s-vsvw-vyyu-, with PerfP -aes-saew-aeyya-, Imprt s-assaw-ayy, LoImpfP
-s-lsw-ayyi-, and VblN a-s-sss-awayy. A similar paradigm is recorded for
A-grm. Underived VblN variant t-ayyaw-t 'leaving, departure', related to
-uyyu- 'leave', points to a possible original *Vyw consonantal sequence for
this stem. However, the development (or presentation) of the w-extension
probably has more to do with the lightness of -uyyu-, with its single geminated
C, and perhaps to the influence of the much more common (double) causative
-s-vs-iwvy- 'send'.
For 'have (sb) kill (sb, sth)', I recorded -s-νητ- in K-d (PerfP -ass-sqra-).
For Burkina, Sudlow (TNEBF 87) records a variant with -svw- (Imprt
"sawanv"). For Niger, LTF2 246 has -s-νηνυ- varying with -s-vs-νηνυ- but
does not confirm the -svw- variant.
Since the Passive has variants -tvw- and -t- (-tt-), I incline to take the
-svw- in 'cause to leave' as just an extension of -s-. Prasse (MGT 6.57)
observes that Caus -svw- is more common in Algeria (Hoggar).