What is a morphophonemic rule?

Definition
	A morphophonemic rule has the form of a phonological rule, but is restricted to a particular morphological environment.

Discussion
	Morphophonemic rules are sensitive to their environment, unlike phonological rules. Whenever morphological information is required to specify the environment for an allophonic rule, the rule is morphophonemic.

Examples

The prefix /in-/ has the allomorphs [il] and [ir]:

/in-/ + responsible	irresponsible
/in-/ + logical	illogical

The rules n G l / __l and n G r / __r are not phonological rules in English, however. If they were, the prefixes /un-/ and /non-/ would also exhibit this regular pattern, but they do not.

/un-/ + responsive	(*urresponsive)	unresponsive
/un-/ + limited	(*ullimited)	unlimited
/non-/ + retroactive	(*nor-retroactive)	non-retroactive
/non-/ + lethal	(*nol-lethal)	non-lethal

Therefore, there must be a morphophonemic rule which determines the allomorphs [il] and [ir] of the prefix /in-/.

Source
	Payne, T.1997a:23–24

Context for this page:

Concept module: morphophonemic rule
In overview module: Glossary (Linguistics): M
In modular book: Glossary of linguistic terms, by Eugene E. Loos (general editor), Susan Anderson (editor), Dwight H., Day, Jr. (editor), Paul C. Jordan (editor), and J. Douglas Wingate (editor)
In bookshelf: Linguistics

This page is an extract from the LinguaLinks Library, Version 5.0 published on CD-ROM by SIL International, 2003. [Ordering information.]

Page content last modified: 5 January 2004