predictable and systematic about the distribution of the allomorphs of these morphemes—namely, that they
all are subject to voice assimilation. What is required is a general statement to the effect that in English
inflectional morphology, a suffix consonant AGREES IN VOICING with the last segment of the stem. But
if the last stem consonant is very similar to the suffix consonant (e.g. if both sounds are coronal stridents)
insert /I/ to separate them. The importance of voice assimilation will become even clearer when we look at
more inflectional suffixes later in this chapter.
5.2.2
Derivations
Underlying representations can be quite different from phonetic representations. To go from
UNDERLYING REPRESENTATIONS in the dictionary entries of morphemes to their actual SURFACE
(PHONETIC) REPRESENTATIONS which occur in speech, phonological representations of morphemes
may go through a metaphorical journey involving modifications at various stages. We will call that journey
a DERIVATION. A derivation entails applying phonological rules which, step by step or, more likely,
simultaneously, alter the underlying representation and bring it closer and closer to the ultimate surface
representation.
As we have already seen, in the case of the /-z/ noun plural and third person verb endings, the derivation
involves two rules:
[5.5]
a. Rule 1:
/
I/
insertion (or
schwa epenthesis)
If the stem-final sound
is a strident coronal, insert /I/ after it. (In some dialects, the vowel inserted is /e/ (e.g.
buses
is pronounced /b sez/). So this rule is also called SCHWA EPENTHESIS.)
b. Rule 2:
Voice assimilation
Make the suffix agree in voicing with the preceding sound if it does not do so already.
(This ensures that the coronal sibilant that is suffixed is voiceless /-s/ after /p t k f /, and voiced /-z/ elsewhere.)
Four illustrative examples of derivations are given in [5.6]:
[5.6]
Underlying
representation
/mæt-z/
/læd-z/
/ u:-z/
/pit -z/
Rule 1
/I/ insertion
inapplic.
inapplic.
inapplic.
/pIt -
Iz/
Rule 2
Voice assimilation
/mæt-
s/
inapplic.
(Already voiced)
inapplic.
(Already voiced)
inapplic.
(Already voiced)
Surface representation
/mæts/
‘mats
/lædz/
‘lads’
/ u:z/
‘shoes’
/pIt Iz/
‘pitches’
The interaction between rules in a derivation is crucially important. Applying the right rules in the wrong
order will yield an incorrect output. Here voice assimilation must not apply before /I/ epenthesis or else we
will get the incorrect output: /pIt -z/ /pIt -s/ /pIt -I-s/ /pIt Is/ *[pIt Is].
ENGLISH WORDS 63
The account of phonological conditioning motivated by voice assimilation which has been provided for
the regular plural (spelt
-s) can be extended to the regular past tense morpheme (spelt
-ed) with very little
modification (see also
section 7.3
). The past tense has three allomorphs. Their selection follows very similar
principles to those that govern the selection of the allomorphs of the noun plural and the third person
singular which we have described:
[5.7]
a.
After the alveolar stops /t/ and /d/ select /-Id/ (or /-ed/
depending on the dialect), e.g.
acted /æktId/,
lifted /
lIftId/,
added /ædId/,
wounded /wUndId/
b. After any voiceless consonant other than /t/ select /t/,
e.g.
taped /teIpt/,
fished /fI t/
, sparked /spa:kt/
, minced /
mInst/
c. After any vowel or any voiced consonant other than /d/
select /d/, e.g.
tamed /teImd/,
boozed /bu:zd/,
waged /
weIdd/cooled
/ku:ld/
If the underlying representation of this morpheme is assumed to be /-d/, a derivation featuring two rules
we have already used in our treatment of inflectional morphemes, namely /I/ epenthesis and voice
assimilation, will account for its surface realisation:
[5.8]
a.
/
I/
epenthesis (or
schwa epenthesis)
In order to prevent two alveolar
stops from being next
to each other, insert /I/ before the suffix /-d/
in cases
where the stem ends in one of the alveolar stops /t/ and /
d/,
e.g.,
added /æd-d/ /æd-
Id/ /ædId/;
lifted /lIft-d/ /lIft-
Id/ /lIftId/
b.
Voice assimilation
The suffix agrees in voicing
with the last sound in the
stem to which it is attached,
e.g.
taped /teIpd/ /teIp-t/ /teIpt/;
tamed teIm-d/ /teIm-d/ (no change) /teImd/
Note again that assimilation
must not apply before
epenthesis lest we obtain the incorrect forms * [lIftIt]
from derivations like /lIft-d/ /lIft-t/ /lIftIt/ *
[lIftIt].
With this we will leave phonological conditioning of
allomorphs and turn to other
factors which determine
the distribution of allomorphs.
64 MASQUERADING ALLOMORPHS
