Phonological
rules may also move phonemes from one place in the string to another. Such
rules are called metathesis rules. They are less common, but they do exist. In
some dialects of English, for example, the word aks is pronounced [aks], but
the word asking is pronounced [askɪŋ]. In these dialects a metathesis rule
‘switches’ the /s/ and /k/ in certain contexts. It is interesting that in Old
English the verb was askian, with the /k/ preceding the /s/. A historical
metathesis rule switched these two consonants, producing aks in most dialects
of English. Children’s speech shows many cases of metathesis (which are later
corrected as the child approaches the adult grammar): aminal [æmənəl] for
animal and pusketti [phəsketi] foe spaghetti are common children’s
pronunciations.
In Hebrew there is metathesis rule that reverses a
pronoun-final consonant with the first consonant of the following verb if the
verb starts with a sibilant. These reversals are in ‘reflexive’ verb forms, as
shown in the following examples :
Phonological rules, then, may produce the following
alterations :
1. Change feature values (vowel nasalisation rule in
English).
2. Add new features (aspiration in English)
3. Delete segments (final consonant deletion in
French)
4. Add segments (vowel insertion in Spanish).
5. Re-order segments (metathesis rule in Hebrew).
These rules, when applied to the phonemic
representations of words and phrases, result in phonemic forms that may differ
substantially from the phonemic form, if such differences were unpredictable,
we would find it difficult to explain how we can understand what we hear or how
we produce utterances that represent the meaning we wish to convey. The more we
look at languages, however, the more we see that many aspects of the phonetic form
of utterances which appear at first to be irregular and unpredictable are
actually rule-governed. We learn, or construct, these rules when we learn the
language as children. The rules represent ‘patterns’ or general principles.
