English noun plurals: Morphophonemics and stem suppletion

Morphophonemics and stem suppletion

Morphophonemics refers to allomorphy which results from regular phonological rules; STEM SUPLETION refers to irregular inflection.

The data

Most nouns form their plural by adding suffix –(e)s, which has three spelling forms: /-z/, /-s/, and /-iz/.

(1)   a. /boI-z/         boy-s

           /tri:-z/                   tree-s

           /kaʊ-z/        cow-s

  1. /tɔp-s/                  top-s

           /bʊk-s/        books

           /hIp-s/                  hips

  1. /bɔk-iz /     box-es

          /rɔz-iz/          ros-es

          /pIt∫-iz/        peach-es

However, other nouns have irregular plurals. A few have identical singular and plural forms.

(2)      Singular         Plural

          Sheep           sheep

          Fish              fish

With others, the singular and plural forms differ in the stem vowel.

(3)      Singular         Plural

          Foot             feet

          Mouse          mice

          Woman         women

          Man              men

With a few, the plural has a suffix that no other stem in the language has. Some nouns have both an irregular suffix and a vowel change.

(4)      Singular         plural

          /ɔks/            / ɔks-Ən/       ox(en)

          /t∫aIld/         /t∫Ild-rƏn/     child(ren)

Other retain the singular/plural inflection from latin , although this pattern is being regularized, i.e., some irregular forms have been replaced by regular ones.

(5)      Singular         Plural

          alumnus        alumni

          octopus        octopi           (traditional, irregular form)

                             octppuses     (colloquial, regularized form)

Morphemes and allomorphs

One morpheme having several different variants is called its ALLOMORPHS. The different allomorphs of a morpheme all have the same meaning. However, they are in  complementary distribution, just like the allophones of a phoneme; in any given context, only one allomorph of the morpheme is possible.

       A morpheme is a consistent and unanalyzable association of phonological, grammatical, and semantic information.


There are several kinds of allomorphy in English noun plurals. The most widespread is the variation in pronunciation of the regular suffix –(e)s, as illustrated in (1). We can attribute it to two phonological process;

(6)      a. assimilation in voicing (/z/ à /s/ after a voiceless segment)

  1. insertion of /I/ to break up clusters of alveolar and alveopalatal consonants.

This type of allomorphy is called MORPHOPHONEMICS and is considered to be a part of phonology, since it has to do purely with the interactions of sounds. The two phonological rules in (6) modify /-z/ to produce the other two variants /-s/ and /-iz/. Together , the three forms /-z/, and /-s/ and /-iz/ are the SURFACE FORMS for the plural morpheme. Inflectional spellout rule for noun plurals:

  For example, suppose we want to generate cats, dogs, and roses. The deep structures are as follows:
The rule in (7) applies to produce (syntactic) surface structure:
These are the input to the phonological rules, which modify the terminal nodes to produce the correct (phonological) surface forms.

Morphophonemics in derivational morphology

      Morphophonemics occurs with both inflectional and derivational morphology. Let’s look at an example involving derivation. Consider the pairs of adjectives listed in (11)

(11) a. elegant                             inelegant

          Eligible                    ineligible

          Tolerant                  intolerant

          Direct                     indirect 

  1. possible                impossible

          perfect                             imperfect

          practical                  impractical

          movable                 immovable

  1. correct                  incorrect

          capable                  incapable

  1. legal                     illegal

          legible                    illegible

          legitimate                illegitimate

  1. e. reverent                irreverent

          regular                    irregular

          reversible                irreversible

There are five allomorphs of the same prefix here: /in-/, /im-/, /iŋ-/,  /il-/, / and /ir-/. The variation is phonologically predictable. If we assume that /in-/ is the underlying form, then it is easy to explain the other four allomorphs as a case of assimilation to bilabial  /m/ before a bilabial, to velar /ŋ/ before a velar, to /I/ before /I/, and to /r/ before /r/.

Phonological rules then immediately change /in-/ to /im-/ before a bilabial stop, etc., so that in the lexical entries, we show the different allomorphs of the prefix.

(13)    A

          In[elIgnt]      not elegant

          Im[præktIkl]  not practicle

          Iŋ[korekt]     not correct

          Il[kigl]           not legal

          Ir[regjƏlƏr]    not regular

Stem suppletion

Not all allomorphic variation is morphophonemics; any that cannot be handled by regular phonological rules is called SUPPLETION or SUPPLETIVE ALLOMORPHY. Suppletion is words that have irregular forms in their paradigms. This is called STEM SUPPLETION. Most of the allomorphy of the English noun plurals discussed above is of this type, involving irregular patterns of suffixation and vowel changes.

(14)    N

          fʊt      [- plural]

          fi:t      [+plural]                 foot

          t∫aIld            [- plural]

          t∫Ild-rƏn       [+plual]        child

          maʊs  [- plural]

          maIs   [+plural]       mouse

the correct surface form is inserted directly from the lexicon in deep structure.

Analyzing allomorphic variation in general

There are three main factors that distinguish different types of allomorphy:

(38)    a. type of variation: morphophonemics versus suppletion

  1. what varies: stems versus affixes
  2. conditioning environment: lexical (arbitrary) or something else (e.g., phonological)

In principle, all three can vary independently, but usually they combine to produce the following four types:

                             Type                                Example
Morphomonemics affecting
stems and/or affixes with phonological conditioning
Regular English noun
plurals English derivational prefix /in-/
Suppletion of stems
Irregular English noun plurals
Suppletion of affixes,
phonological conditioning
possessor agreement
Suppletion of affixes,
lexical conditioning
subject agreement