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What is lexical phonology?



Lexical phonology is an approach to phonology that accounts for the interactions of morphology and phonology in the word building process.


The lexicon plays a central, productive role in the theory. It consists of ordered levels, which are the domain for certain phonological or morphological processes.


Here is a diagram of the overall structure of the lexical phonology model:


The following are crucial components of lexical phonology:

  • Lexical and post-lexical rules

    Here is a table that compares lexical and post-lexical rules:

    Lexical rules …

    Post-lexical rules …

    Apply only within words.

    Apply within words or across word boundaries.

    Are prone to exceptions.

    Do not have exceptions.

    Require morphological information.

    Require syntactic information, or no grammatical information at all.

    Must be structure-preserving.

    Are not necessarily structure-preserving.

    Will not be blocked by pauses.

    Can be blocked by pauses.

    Apply first.

    Apply later.

  • Levels

    English has between two and four levels of morphology in the lexicon. The levels within the lexicon are ordered so that, to get to Level 3 from Level 1, a word must pass through Level 2. A word cannot go back to a previous level once it has left one level and gone on to another level.

    Halle and Mohanan propose the following four levels of morphology in the lexicon:

  • Level 1: Class 1 derivation, irregular inflection
  • Level 2: Class 2 derivation
  • Level 3: Compounding
  • Level 4: Regular inflection
  • We will consider the first two levels of affixation because they differ significantly. Here is a table that compares affixation on Levels 1 and 2:

    Level 1

    Level 2

    Affixes include:

    -ate, -ion, -ity, -ic, sub-, de-, in-

    Affixes include:

    -ly, -ful, -some, -ness, re-, un-, non-

    Affixation causes stress shift:


    Affixation does not affect stress:


    Trisyllabic shortening occurs:


    No trisyllabic shortening occurs:


    Nasal assimilation occurs:

    in + legal -> illegal

    Nasal assimilation is blocked:

    un + ladylike -> unladylike, not *ulladylike

    Affixes may attach to stems:

    re-mit, de-duce

    Affixes attach only to words:

    re-open, de-regulate

    Affixation is less productive and more exception ridden.

    Affixation is more productive and less exception ridden.


    Durand 1990 178

  • Bracket erasure convention

    The bracket erasure convention is an important convention in lexical phonology. It ensures that the morphological brackets introduced within a certain level are erased before entering the next level.


    Here is an example of the bracket erasure convention. The brackets in pressurize are erased before it enters Level II.

    Level I

    [press] [-ure] [-ize]


    [press] [-ure]


    [[[press] [-ure]] [-ize]]

    Level II

    [re-] [pressurize] (Bracket erasure)


    [[re-] [pressurize]]

Examples (English)

Here is an example of an application of lexical phonology:

  • Here are the words to be considered in this example:

    • sane [sejn] / sanity [sQnIti]
    • neighbor [nejb«&u0279;] / neighborhood [nejb«&u0279;hUd] *[nQb«&u0279;hUd]
  • The following rule applies across level 1 morpheme boundaries:

  • A tense vowel becomes lax when a short word is lengthened by adding a suffix, so that the words ends up having at least three syllables.


    Katamba 1989 139

  • This derivation demonstrates affixation in lexical phonology accompanied by the application of a phonological rule, trisyllabic shortening.

  • Sources

    Durand 1990


    Katamba 1989


    Mohanan 1986

    Context for this page:

    Go to SIL home page 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

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