There are three parts to a phonological rule
- The sound(s) affected by the rule
- The environment where the rule applies
- The result of the rule
Conditioning environment- the environment in which the rule applies
Natural class- a group of sounds in a language that share one or more articulatory or auditory property, to the exclusion of all other sounds in that language
- Ex) /t/ and /d/ are the natural class of alveolar (oral) stops
- Can be used to describe both the sounds affected by a rule and the environments where a rule applies
More properties to describe sounds and natural classes:
- Sibilant- segments that have a high-pitched, hissing sound quality ([s], [ʃ], [tʃ], [z], [ʒ], [dʒ])
- Labial- referring to [f] and [v] together with [p], [b], [m], [w], and [w̩]
- Obstruents- produced with an obstruction of the airflow (fricatives, stops, and affricates)
- Sonorants- produced with a relatively open passage for airflow (nasals, liquids, glides, and vowels)
Types of Phonological Rules
- Assimilation- causes a sound to take on a property from a nearby, often adjacent, segment
- Palatalization- a special type of assimilation in which a consonant becomes like a neighboring palatal
- Dissimilation- causes two adjacent sounds to become less similar with respect to some property, by means of a change in one or both sounds
- Insertion- causes a segment not present at the phonemic level to be added to the phonetic form of a word
- Deletion- eliminates a sound that was present at the phonemic level
- Metathesis- changes the order of sounds in order to make words easier to pronounce or understand
- Strengthening- make sounds stronger
- Aspiration- voiceless stops become aspirated when they occur at the beginning of a stressed syllable
- Weakening- cause sounds to become weaker
- Flapping- an alveolar stop is realized as [ɾ] when it occurs after a stressed vowel and before an unstressed vowel
Obligatory rules- a rule that always applies in the speech of all speakers of a language or dialect having the rule, regardless of style or rate of speaking
Optional rules- a rule that may or may not apply in any given utterance, and are responsible for variation in speech