The unaffixed form bit
0
forms a perfective with the addition of a prefix. Adding a
different prefix, however, both makes a perfective and creates a new lexical form,
from which a new imperfective has to be derived by the addition of a suffix. This
pattern is enormously productive. However, some verbs do not perfectivize when
prefixed, while some are perfectivized by suffixation. A few verbs are perfective
without being affixed. The semantic changes brought about by prefixation vary
from neutral perfectivization to ‘‘sublexical’’ modification in the so-called
‘‘Aktionsarten’’ (or ‘‘procedurals’’, 8.3.1.3), and genuine lexical modification as
happens with ubı
´
t
0
above. And the choice of ‘‘neutral’’ prefix may differ for a given
verb between languages.
Stems and aspect As a starting-point, it is useful to consider some default cases.
As Brecht shows (1985: 12), simplex verbs like bit
0
are usually atelic – that is, they
do not indicate any clear termination-point – and imperfective. So are prefixed-
suffixed verbs, like ubiva
´
t
0
. Prefixed, non-suffixed verbs like ubı
´
t
0
are usually telic
and perfective. There are only a few simplex (unaffixed) perfectives, which tend to
be among the common verbs:
(35a) ‘give’: Rus da-t
0
, Ukr da
´
-ty, B/C/S da``-ti,Czda
´
-t
‘buy’: Rus kup-ı
´
t
0
, Bel kup-ı
´
c
0
,Czkoup-it, Blg ku
´
p-ja, Sln kup-ı
´
ti
(cf. B/C/S ku
´
p-iti is [Imprfv], the [Prfv] being prefixed s-ku
´
piti)
Other verbs of this sort are telic:
(35b) ‘sit down’: Rus ses-t
0
, Ukr sı
´
s-ty, B/C/S se``s-ti (all ¼ root sed-)
Some apparently unaffixed perfective verbs are in fact etymologically prefixed, e.g.
Rus skaza
´
t
0
‘say’ (s-kaz-), vzjat
0
‘take’ (vz-ja-), uda
´
rit
0
‘strike’ (u-dar-). They not
infrequently have suppletive related imperfectives (e.g. Rus govorı
´
t
0
‘say’, brat
0
‘take’).
Adding prefixes to unaffixed perfective verbs results in semantic changes con-
sistent with the properties of the prefix, and the resulting verb is also perfective (e.g.
Rus ot-da
´
t
0
‘give back’). Imperfectives are derived from such verbs either by
suffixation (the norm), typically -(i)va- or -ja-, e.g. B/C/S o-da
´
-va-ti ‘betray, give
away’, u-bı
´
-ja-ti ‘kill’, or are provided by the suppletive verb.
As we have seen in chapter 5, there are only relatively few completely unsuffixed
imperfective verb stems (i.e. lacking even a thematic vowel) like PSl nes-ti ‘to
carry’. Most verbs have either a thematic vowel which is added to the root to
form the verb stem, as in PSl pis-a-ti ‘to write’; or they have a suffix which creates a verb,
often from a non-verbal root, as in Rus u
´
zˇin-a-t
0
, ‘to have dinner/supper’ ( < noun
u
´
zˇin). Such verbs are usually inherently imperfective, and form their perfective by
442 8. Word formation