Phonology, part 4: Natural Classes and Features

November 2, 2012

Solving Phonology Problems• Let’s walk through the practice exercises from last time

together…

Generalities• Sometimes, the rules for one phoneme’s distribution are identical to the rules for another phoneme’s distribution.

• /t/ [t] / after [s]

/t/ [th] / at the beginning of stressed syllables

[thap] ‘top’ [stap] ‘stop’• /p/ [p] / after [s]

/p/ [ph] / at the beginning of stressed syllables

[phæt] ‘pat’ [spæt] ‘spat’• /k/ [k] / after [s]

/k/ [kh] / at the beginning of stressed syllables

[khar] ‘car’ [skar] ‘scar’

Natural Classes• The same rules apply to /p/, /t/ and /k/. Why?

• /p/, /t/ and /k/ form a natural class of sounds in English.

• They are all voiceless stops

• No other sound in English is a voiceless stop

• A natural class is set of sounds in a language that:

• share one or more (phonetic) features

• to the exclusion of all other sounds in that language.

• …and function together in phonological rules.

• The phonetic “features” primarily include the phonetic labels we’ve already learned.

• …although we’ll need to make some additions.

Natural Class Examples• For instance, in English:

1. [k], [g], form the natural class of velar stops

2. [u] and [o] form the natural class of rounded, tense vowels.

• What natural classes are formed by the following groups of sounds?

• [t], [s]

• [v], , [z],

• , ,

This is actually useful.• Phonological patterns are often formed by natural classes of sounds.

• Ex: the (regular) English past tense exhibits allomorphy.

• Allomorph 1: [d]

study studied fear feared

mail mailed loan loaned

• Allomorph 2:

collect collected mate mated

wade waded need needed

• What’s the natural class of segments that induces the change?

New Features• There are a few features in phonology that are more general than the ones we find in phonetics.

• For instance: the Arabic Sun and Moon letters.

• What’s the pattern?

• The “Sun letters” include alveolars, post-alveolars and interdentals

• = sounds made with the front part of the tongue

• The “Moon letters” include everything else.

• New feature: [CORONAL] is a cover term for alveolars, post-alveolars and interdentals.

Assimilation• The change undergone by the definite article in Arabic is called assimilation.

• = when one sound becomes more similar to another in its environment.

• In the Arabic case, there is complete, or total assimilation.

• …but individual features can also change, as in place assimilation.

• Ex: In English, /n/ often takes on the place of articulation of a following consonant.

• ‘unpleasant’

• ‘engrossed’

More Assimilation• Remember this pattern?

• Plural forms:

cat: dog:

match: judge:

chair: pass:

hose: puck:

• The basic form of the plural is [z].

• It exhibits voicing assimilation when following voiceless segments…

• becoming voiceless [s].

More Assimilation• Remember this pattern?

• Plural forms:

cat: dog:

match: judge:

chair: pass:

hose: puck:

• The basic form of the plural is [z].

• It becomes when it follows [s], [z], or .

• These are [strident] consonants.

Some New Features• Only CORONAL consonants can be [strident].

• “strident” = noisy

• Other place of articulation features:

• LABIAL (involves the lips)

• includes both bilabials and labio-dentals

• [p], [b], [m], [f], [v]

• DORSAL (involves the back of tongue)

• includes both palatals and velars

• [k], [g], [j]

Distinctive Features• The features used to describe natural classes of sounds in phonology are known as distinctive features.

• …because they distinguish between otherwise identical sounds.

• The distinctions made by features are (almost always) denoted by a [+] or [-] in front of the feature name.

• For instance, stops and fricatives are distinguished by the feature [continuant].

• [s] = [+continuant] (air flows steadily through mouth)

• [t] = [-continuant] (air does not flow steadily through mouth)

• (Note: nasals and affricates are also [-continuant])