Lecture 18: Phonology IVLecture 18: Phonology IV[This is a brief sketch of the class notes and overheads used on 11/11. As usual, no guarantee of completeness is given, and these notes are intended to supplement rather than to replace regular attendance in class.]
Although we have seen that phonological rules vary from language to language, and are thus somewhat arbitrary, it is nevertheless true that there are striking and simple regularities in what many phonological rules do. One common type of phonological rule is an assimilation rule: this is a rule that makes two or more neighboring segments more similar by making the segments share some feature. We have seen a number of examples of this in English.
The vowel nasalization rule in English is an assimilation rule, because it involves taking the [+nasal] feature on the segment following the vowel and adding it to the vowel, making the value of [nasal] identical for the two segments.
The liquid devoicing rule in English is also an assimilation rule, but in this case it involves the transfer of a feature, in this case [-voice] from a preceding segment onto a liquid segment.
The rule which changes [t] to [d] in intervocalic position in American English dialects is an assimilation rule, because it takes a sequence of segments with the features [+voice] [-voice] [+voice] and turns it into a sequence of three [+voice] segments.
This rule is not an assimilation rule, because there is no sense in which the aspiration that appears on the voiceless stops when they are in syllable initial position is transferred from some neighboring segment.
Similarly, the rule which lengthens vowels when they precede voiced stops is not an assimilation rule.
Question: does this feature of Southern American English have the effect that vowel length is phonemically contrastive in Southern US English, making it like Japanese and unlike Northern American English? The way to test this is to find out whether Southern American speakers make a systematic difference in the way they pronounce "pod" [pad] and "pied" [pa:d], or "trod" [trad] and "tried" [tra:d].
Some well-known dialects of English contain a phonological rule which deletes /r/ in syllable final position. We can, however, show that speakers do represent the /r/ phonologically in words like "car" and "dinner", because the /r/ reappears when these words are followed by words beginning with a vowel, with the consequence that the /r/ is now syllable-initial rather than syllable-final.
