Phonological rules in the lexicon

 

In an inheritance lexicon, phonological rules can be defined at, or near to, the top of the phonological hierarchy. They will then be inherited by default by all the phonological objects that lie below them in the hierarchy.

For example, in German, final consonant devoicing (FCD) applies to stems which appear either uninflected or with inflectional suffixes which do not begin with a vowel. The rule thus has to check the suffix of the form in question. If there is a suffix which begins with a vowel, then no devoicing takes place. If there is no suffix, or the suffix begins with a consonant then devoicing does take place. This rule can be defined by the following equation (which forms part of our definition of the German Word node):

Word:
    <phn syl1 form> == "<phn syl1 onset>"
                       "<phn syl1 peak>"
                       IF:<VOWEL:<"<mor suffix>">
                       THEN       "<phn syl1 coda>"
                       ELSE  FCD:<"<phn syl1 coda>">>.

Here the path-initial attribute phn in <phn syl1 coda> contrasts with the path-initial mor in <mor suffix>. These path-initial attributes (along with syn and sem) serve to divide the feature space into phonological and morphological domains, respectively.

Exercise 6018

Define a phonological rule for the nasal assimilation that takes place in English prefixation.

Exercise 6019

Say, informally, exactly what it is that the FCD function has to do to the coda of the final syllable. Then use IDEM and Devoice, as defined in the section on finite state transducers above, to give a formal DATR definition for the FCD function.