3.2 Phonological rules and processes

Understanding Phonological Rules and Processes

Phonological rules describe how the sounds stored in your mental dictionary (underlying forms) get transformed into the sounds you actually produce in speech (surface forms). They capture the systematic, predictable patterns that govern pronunciation in every language.

These rules matter because they explain things that seem random at first. Why does the English plural end in [z] in "dogs" but [s] in "cats"? Why do some sounds disappear in casual speech? Phonological rules reveal the logic behind these patterns, and they connect to how our mouths physically produce sounds.

Nature of Phonological Rules

Phonological rules map underlying representations (the abstract forms stored in your mind) to surface forms (what you actually say). The underlying form of the English plural suffix, for example, is /z/. But after a voiceless consonant like /t/, it surfaces as [s] because your vocal cords are already "off" from the previous sound.

These changes aren't random. They're motivated by factors like:

• Ease of articulation: your mouth naturally takes shortcuts to make speech smoother
• Perceptual clarity: some changes help listeners distinguish sounds more easily
• Language-specific conventions: each language has its own set of rules, which is why the same sound can behave differently across languages

Phonological rules also maintain important contrasts. They ensure that sounds change in predictable environments without collapsing distinctions that carry meaning.

Classification of Phonological Processes

Each process below describes a different type of sound change. Most of them make speech easier to produce or perceive.

• Assimilation: A sound becomes more similar to a neighboring sound. This is the most common process across languages. It can be regressive (a sound changes to match the one after it, like "input" pronounced as "imput" because /n/ assimilates to the bilabial /p/), progressive (a sound changes to match the one before it, like the plural /z/ becoming [s] after voiceless sounds), or reciprocal (two sounds influence each other simultaneously).
• Dissimilation: The opposite of assimilation. A sound becomes less similar to a nearby sound to increase contrast. The Latin word "arbor" became "árbol" in Spanish, where the second /r/ changed to /l/ to avoid two /r/ sounds close together.
• Deletion: A sound is removed entirely. Syncope is deletion of a mid-word vowel (like "chocolate" often pronounced as two syllables: "choc-late"). Apocope is deletion of a word-final sound (like dropping the final /ə/ in Old English words over time).
• Insertion (epenthesis): A sound is added, usually to break up a difficult consonant cluster. In English, many speakers insert a [p] between /m/ and /s/ in "hamster," producing something like "hampster."
• Metathesis: Sounds swap their order within a word. Some English dialects pronounce "ask" as [æks], reversing the /s/ and /k/. The Old English word "bridd" became "bird" through metathesis.
• Lenition: A consonant weakens, often between vowels. In Spanish, /b/ becomes the fricative [β] between vowels (e.g., "lobo" [loβo]), because fully closing the lips takes more effort in that position.
• Fortition: A consonant strengthens, often at the beginning of a word or under stress. This is less common than lenition but occurs when a language reinforces consonants in prominent positions.

Application of Phonological Rules

Phonological rules are written in a standard notation that looks like this:

This reads: "A becomes B in the environment where X precedes it and Y follows it." The blank line (__) shows where the sound in question sits relative to its neighbors.

Here's how to apply a phonological rule step by step:

1. Identify the underlying form. Start with the abstract representation stored in the speaker's mental lexicon (e.g., the plural morpheme is /z/).
2. Check the environment. Look at what comes before and after the target sound. Does it match the context specified in the rule?
3. Apply the rule. If the environment matches, transform the sound as the rule dictates (e.g., /z/ → [s] after a voiceless consonant).
4. Consider rule ordering. When multiple rules could apply, order matters. A feeding relationship means one rule creates the input for another. A bleeding relationship means one rule removes the input that another rule would have needed.
5. Produce the surface form. After all applicable rules have been applied in order, you have the pronunciation that speakers actually produce.

Analysis of Phonological Data

When you encounter phonological data on a problem set or exam, you're typically given a set of words and asked to figure out the rule. Here's a reliable approach:

1. Collect and organize the data. List the forms side by side, noting where sounds alternate (e.g., a sound that appears as [p] in one form but [b] in another).
2. Look for patterns. Ask: In what environment does each variant appear? Check the surrounding sounds, position in the word, and stress.
3. Formulate a tentative rule. Write it in standard notation. Be as specific as the data requires, but no more specific than necessary.
4. Test the rule. Apply it to all the data. If it generates the wrong output for any form, revise.
5. Consider alternatives. A constraint-based approach (like Optimality Theory) doesn't use ordered rules. Instead, it ranks universal constraints, and the winning surface form is the one that best satisfies the highest-ranked constraints. Your course may or may not cover this framework.

Comparing patterns across languages can also help. Many phonological processes (like voicing assimilation and vowel harmony) show up in unrelated languages, suggesting they reflect universal tendencies in how humans produce and perceive speech.