DISTINCTIVE FEATURE THEORY
The Phoneme Theory has established, among other things, that the phoneme is the smallest
distinctive/contrastive unit of sound in language. A closer look at some of the phonological
generalizations in language reveals that this is far from being the case. Rather, the speech
sounds are themselves composed of yet smaller features that make up the articulatory gesture.
Such features enable particular sounds to behave or operate as units or family of sounds.
An example of the generalizations referred to above include the English Plural Rule,
illustrated below:
a.
b.
c.
boys [bojz]
backs [bæks]
church [ʧæʧiz]
pad [pædz]
fits [fits]
races [ræsiz]
pens [penz]
tracks [treks]
judge [ʤʌʤiz]
From the three sets of examples above, it is apparent that the realization of the plural
morpheme /z/ is not random. Its realization depends, from the examples above, on the last
consonant sound of the word. If, for the case of set (a), the last consonant is voiced the plural
morpheme would be realized as [z]. In cases whereby the last consonant sound is voiceless,
as in (b), the plural morpheme is realized as [s]. In cases whereby the last consonant sound is
a sibilant sound, as in (c), the plural morpheme is realized as [iz]. What comes out from the
examples above is that the realisatiuon of the plural morpheme is systematic; it is not random.
Its realization is conditioned by a particular group fo sounds which share a particular
characteristic. In the case of the plural morpheme in English, this characteristic/feature is
voicing.
Unitary behaviour of sounds can also be illustrated using the English Aspiration Rule.
a.
b.
c.
tip
[th ip]
dip
[dip]
sip
[sip]
peep
[ph ip]
beep
[bi:p]
van
[væn]
keep
[kh i:p]
geek
[gi:k]
sheep [ʃi:p]
From the examples above one can deduce that aspiration occurs when the first sound in the
word is a voiceless stop- not just a stop or any other voiceless sound.
Thus the Plural and Aspiration Rules allow us to state generalizations that would be
otherwise missed by a mere listing of phonemes in a language. The two rules exemplify an
important point about determining which phonetic features of a language are in fact
significant for the theory of phonology. In the case of the Plural Rule the feature of voicing is
important. For the Aspiration Rule voicing and ‘continuancy’ are equally important. The
significant phonetic features of human language that play a crucial role in the statement of
phonological rules are called distinctive features. Akmajian et al (2001) states,
… the point- and manner-of-articulation features represent a prima facie
acknowledgement that speech sounds can be characterized by the phonetic
features that make up these sound.
Distinctive features are not only restricted to formulation of generalizations on phonological
rules. As Fromkin and Rodman (1993:73) observe,
in order for two phonetic forms to differ and to contrast meanings, there
must be some phonetic difference between substituted sounds.
Minimal pairs can be used to illustrate this point. For example,
team/ream
feel/veal
When two sounds are exactly alike phonetically except for one feature, the phonetic
difference is distinctive.
Distinctive features
In their Sound Pattern of English Chomsky and Halle (1968) view features as binary. That
is, as having one of two values: either a plus value (+), which indicates the presence of the
feature, or a minus value (-) which indicates the absence of the feature. By convention,
distinctive features are enclosed in square brackets [ ].
All phonemes in the SPE are regarded as bundles of features. That is as groups of binary
features with pluses and minuses. As such the features allow us to distinguish all the
phonemes (consonant as well as vowel) from each other and at the same time to refer to
classes of sounds- the class of voiceless consonants. A group of sounds that share a feature is
referred to as a natural class. Distinctive features are not peculiar to English. They are
universal features, which apply to language in general.
Features are classified into five major classes.
1. Major class features.
a. [consonantal]- this feature is used to distinguish consonants from
vowels. Phonemes with the feature [+consonantal] are formed in the vocal
tract with an obstruction that is at least as narrow as that of a fricative.
That is:
i. [+consonantal]- /p/, /b/, /m/, / ʃ /, /s/, /k/, /ʧ /.
ii. [-consonantal]- /a/, /o/, /i/,/j/.
b. [syllabic]- distinguishes sounds that can function as syllable peaks/nuclei
from those that function as margins. That is:
i. [+syllabic]-sounds that function as syllabic peaks. That is syllabic
sounds. Vowels are specialized to perform this function due to their
sonority. /a/, /e/ and /i/ are examples of [+syllabic] sounds.
ii. [-syllabic]- are mainly consonants. These function as margins in
syllables- /s/, /k/, /t/, / ʧ /, / ʤ /
c. [sonorant]- distinguishes sounds that are normally/naturally voiced from
those that are naturally voiceless.
i. [+sonorant]- are produced with a vocal tract cavity which enables
spontaneous voicing. These sounds are thus naturally voiced.
Examples of such sounds include :
1. vowels- /a/, / æ /, / ə /, / i /, /o/
2. nasals - /m/, /n/, /ɲ /, / ƞ /
3. liquids- /r/, /l/
ii. [-sonorant]- are naturally voiceless. These sounds make the
distinction ‘voiced/voiceless’. Examples of such sounds include
1. stops- /t/, /p/, /d/, /b/, /k/, /g/
2. fricatives- /f/, /v/, / ʃ /, / ʒ /, /s/, /z/, / /, / /
3. affricates- /t /, /d /
2. Manner features- represent the vertical relationship between the active and
passive articulators. They therefore determine whether there is complete contact
between the articulators or there is open approximation. Features classified under
manner are:
a. [nasal]- this feature specifies whether the airflow has passed through the
nasal cavity.
i. [+nasal]- phonemes which have this feature are produced with
accompanying lowering of the velem. Examples include- /m/, /n/
and /a/
ii. [-nasal]- are produced with a raised velum. Airflow is through the
oral cavity only. Examples of such phonemes include- /w/, /j/, /s/, /
/, /p/ and /l/.
b. [continuant]- this feature determines whether there has been complete
blockage of the airflow during articulation of the speech segment.,
i. [+continuant]- sounds are produced without a complete blockage
of the air stream. Examples include1. fricatives- /f/, /v, / /, / /
2. liquids- /l/
3. glides/w/, /j/
ii. [-continuant]- are articulated with a complete blockage of the air
stream. Examples include:
1. stops/t/, /d/, /g/
2. nasals
/m/, /n/
3. affricates /t /, /d /
c. [lateral]- phonemes articulated with a complete central blockage in the
oral cavity but with the air stream escaping through one or both sides if the
tongue. /l/ is the only [+lateral] segment in English. All the remaining
segments are [-lateral] (in English).
d. [delayed release]i. [+delayed release]- segments whose production start as that of a
stop but the release is secondarily/gradually made into that of a
fricative. Affricates are classified using this feature. Examples are/t /, /d /. The rest of the sounds are [-delayed release].
3. Place features- these features specify the place of articulation.
a. [labial]- a labial articulation involves a bringing together or closing
together of the lips. That is the active involvement of the lips. [+labial]
phonemes include: /f/ /v/ and /m/
b. [round]- a round articulation involves an extension and pursing of the
lips. All [round] sounds are redundantly [+labial]. That is, they are in
turn/obviously [+labial] since the feature [+round] refers to lip rounding.
However, [+labial] does not necessarily mean or entail [+round].
Examples of [+round] sounds include:/o/, /u/ and /w/
c. [coronal]- in articulating a [+coronal] phoneme, the blade (front part) of
the tongue is raised toward or touches the teeth, the alveolar ridge, or the
pre-palatal region/ alveo-palatal area. [+coronal] sounds include: / /, / /,
/n/, /s/, /l/, /t / and / /.
d. [anterior]- anterior sounds are made with the primary constriction in
front of the alveo-palatal position. Thus labial, dental and alveolar
articulations are [+anterior].
e. [strident]- [+strident] sounds are characterized by the high-frequency
turbulent (hissing) noise that accompanies the production of some
fricatives and affricates. Examples include:/s/, /z/, / /, / /, /t / and /d /.
[+strident] sounds are generally referred to as sibilants. It should be
however noted that not all fricatives are [+strident]. Sounds like / / and / /
are not [-strident].
4. Dorsal features. These specify placement of the tongue. That is, what part of the
tongue is involved during the articulation of the phoneme.
a. [high]- in articulating [+high] phonemes, the body of the tongue is raised
toward or touches the roof of the mouth.
b. [back]- [+back] segments are made with the back of the tongue raised
towards or touching the velum.
5. Laryngeal features- represent the ‘states’ of the glottis.
a. [voiced]- [+voiced] are produced with an accompanying vibrating glottis.
That is, the vibration of the vocal cords.
CONCLUSION
1) Distinctive Feature Theory does not assume that the segment (or the phoneme) is the
ultimate/smallest unit of phonological analysis.
2) Segments as composed of smaller articulatory gestures- referred to as features. These
are units of phonological structure that make up the segment.
3) Features are independent and coordinated elements.
4) Features are binary; they can either be present or absent.