In many areas of scientific research, data is gathered and classified according to properties shared by the phenomenon studied. Phonetics is the science of describing and classifying sound segments (phonemes) according to specific features they have in common. Any sound in the natural speech of any language is discernible based on such features, which are the smallest units of distinction between any two phonemes. In fact, changing one feature of any given phoneme will yield a different sound.
For instance, the phoneme [k] in English is distinguished from all other phonemes when described by its features: [ voiceless, velar, non- aspirated stop]. No other phoneme belongs to this category. Furthermore, if the voicing feature is altered, then [k] becomes changes to [g], which is [ voiced, velar, non-aspirated stop]. And no other phoneme belongs to this category. If place feature of [g] becomes alveolar instead velar, [g] becomes [d].
Features can be used not only to describe singular sounds, but also to arrange them in groups or classes. Take, for example, [t] and [d] in English. These phonemes can be described using two features:
The only two phonemes in English which bear both features are [t] and [d]. Since there are no other phonemes which can be included in this category, we can say we’ve formed a natural class. Using the features voiced and stop/plosive forms a class composed of [d], [b], [g] to which no other phonemes in English can be added.
It is interesting to note that, in general, when classifying phonemes into broad categories, we need less features. The more features used, the fewer number of sounds will belong to that particular category.
For instance, if we want to create a category of all consonants in English which are produced using the lips, we have the category labials. This would include [p, b, m, f, v, w]. By adding a second feature, we reduce the possibilities of which phonemes may be included in this class. If place of articulation is specified, then we will narrow our categories to either bilabials [p,b,m,w] or labiodental [f,v]. If we specify manner of articulation, we will have stops [p,b], fricatives [f,v] nasal, [m], 0r glide [w].
If we want to describe all the consonants which are produced with the tongue against the alveolar ridge, we can simply use the term alveolar which includes [t, d, n, s, z, l, r]. If we want to combine the two categories labials and alveolars we have the class anterior. Anteriors are phonemes that are produced with the tip of the tongue against the alveolar ridge and forward toward the lips, i.e., alveolars, interdentals, labiodentals, and bilabials [t, d, n, s, z, l, r, p, b, m, θ, ð, w]. As you can see, this is a much larger category which can be very useful in describing certain types of phonological rules in many languages.
Below is a list of the broadest classes of features which are often organized in binary distribution such that if a group of phonemes belongs to one category, it generally cannot belong to the other. This ultimately depends, of course, on the specific constraints of each language. It is important to note here that not all of the literature on this subject arranges the features of sounds in exactly the same way.
Major Class Features
The broadest distinguishing category of speech sounds is [±consonantal] [±cons]. In most languages phonemes are either/or. [+cons] phonemes are produced with some type of obstruction of airflow produced as articulators create constriction of the vocal tract. These include plosives (stops), fricatives, affricates, nasals, trills, approximants, ejectives and implosives, while [-cons] phonemes are produced with no constriction. In most languages this category is restricted to vowels.
Another class is [± sonorant] [±son]. [+son] describes phonemes that are produced with relatively free airflow since there is little or no constriction of the articulators. These sound segments are said to be ‘sing-able.’ In other words, they can sustain resonance. Approximants, liquids, glides, nasals, and vowels are included in this class. [-son] is also sometimes referred to as [+obstruent]. These phonemes are articulated with noticeable air obstruction, i.e., stops, affricates, fricatives, ejectives, and implosives.
The third major class is [±syllabic] [±syll] . [+syll] phonemes are considered the most sonorous segments of a language and are singularly permitted in the nucleus position of a syllable, whereas [–syll] are not. This distinction is language specific. Certain languages, such as English, German, Swahili, and Yoruba have phonemes which are [+cons] and [+syll] and behave like a vowel in that they constitute the peak of sonority in a syllable.
Four Way Distinctions for Consonantal and Syllabic
syllabic consonants + +
consonants + -
vowels - +
glides - -
Note that in certain languages approximants are [-cont] [-syll].
Continuants [± continuant] [±cont] are described in terms of sustained obstruction of airflow through the oral cavity. The class [+cont] includes fricatives, liquids, glides, as well as vowels. In the production of these phonemes, the vocal tract is always slightly open, allowing the passage of airflow with varying degrees obstruction. For example, in English, during the production of labiodentals [f,v] and interdentals [θ,ð] a continual flow of air passes through a narrow opening between the lips and the teeth. Although there is obstruction, it is partial and airflow is never completely cut off. In the production of glides and liquids, the air passes through a wider area of the oral cavity with no constriction of the articulators.
Non-continuants [-cont] include stops, (oral and nasal) and affricates which are complex phonemes that begin as a stop and almost instantaneously transition to a fricative. They are classified as non-continuants due to the total closure of the oral cavity at the onset of production. Although in the production of nasals the passage of air is not completely obstructed at any point, air does not pass through the oral cavity thus they are considered non-continuants.
Here are a few more features that are sometimes needed for making more detailed distinctions.
[±nasal] [±nas]: This feature may apply to either consonants or vowels and describes phonemes that are articulated with a lowered velum (soft palate) such that airflow is directed through he nasal cavity.
[±lateral] [±lat]: This feature describes the manner by which air passes laterally across and around the tongue.
[±delayed release] [±del rel]: This feature is used mainly to differentiate a stop release from a fricative release when comparing stops and affricates. Some phonologists will use this feature for all or most phonemes bar stops.
Four Way Distinctions for Sonorants and Continuants
stops (affricates) - -
fricatives - +
nasals + -
liquids, glides, approximants + +
*Note that in certain languages approximants are [-cont]
Labials [±lab] are any phoneme that is produced with the lips as an active articulator and includes bilabials and labiodentals. [p], [b], [m], [f], [v], [w].
Round [±rd] is a feature attributed to phonemes (consonants and vowels) that are produced with the lips rounded. The distribution of rounding is very language specific. In English [+rd] phonemes incluse:[w, u, o]
Anteriors [±ant] are produced with the active articulator positioned toward the alveolar ridge and forward toward the lips. This includes alveolars,alveolar-dentals, interdentals, labiodentals, and bilabials. [p], [b], [m], [w], [f], [v], [θ], [ð], [t], [d], [s], [z], [n], [l], and [r].
Coronals [±cor] are phonemes which are articulated with the tongue against anywhere between the alveolar ridge and the hard palate. This includes alveolars, psot-alveolars, and palatals. [θ], [ð], [t], [d], [s], [z], [n], [∫], [ʒ], [t∫], [dʒ], [j], [l], [r] *[j]
*Some phoneticians do not consider glides to be consonantal. Check with your textbook or professor.
It is interesting to notice that alveolars belong to both the coronal and anterior classes, whereas labials are only anteriors, palatals are only coronal, and velars are neither. This type of classification facilitates the understanding of certain phonological observations which will be discussed later.
Dorsal [±dor] These are sounds articulated with the body of the tongue and includes palatals, velars, and uvulars, as well as all vowels. In Standard English those phonemes included in this class are [k, g, ŋ, j, w].
Subcategories which specify more setailed information about the position of the dorsum are:
[+high] are sounds produced with the dorsum raised such as [[k, g, ŋ, j, w, i, ɪ, u, ʊ]. [-high] are sounds produced with the dorsum lowered such as mid and low vowels and all [-high] consonants.
[+low] are sounds produced with the body of the tongue lowered such as [a,α,æ]. [-low] are all sounds which are not [+low].
[+bck] are sounds produced with the body of the tongue behind the hard palate and includes velars and back vowels [k, g, ŋ, w, ə, ʌ, o, √, u, ʊ, o, ɔ, ɒ].
[-bck] are all sounds which are not [+bck], i.e., front vowels and palatals.
Pharyngeal [±phar] These are sounds made with the root of the tongue against or towards the pharyngeal wall. These do not exist in Standard English.
These feature classes allow us to recognize both basic and complex phonological rules by revealing patterns which are based on the various features of groups of phonemes and how they are allowed to interact.
labial coronal dorsal
bilabial dental alveolar Post-alveolar Alveo-palatals palatal velar uvular pharyngeal glottal
Laryngeal [±lar] or [±voice] [±vce]
[+vce] are sounds made with the vocal folds vibrating. [b, d, g], nasals, liquids, etc.
[-vce] are sounds made without the vocal folds vibrating. In Standard English these include
[p, t, k, ʃ, tʃ, h].
[±spread glottis] [+spread glottis] are sounds which are aspirated whereas [-spread glottis] are non-aspirated sounds.
[±constricted glottis] [+constricted glottis] are sounds produced with the glottis closed such as [ʔ] in Standard English.
[±strident] These are sounds made with increased stricture or closure between the passive and active articulators thus are considered ‘noisy.’
[+str] include [θ, ð, s, z, ʃ, ȝ, tʃ, dȝ].
[ –srt] include [θ, ð, t, d, n, l, ɹ].
[± sibilants] Sibilants are also produced with a great amount of friction or hissing noise and include coronal fricatives and affricates. [s, z, ∫, ʒ, t∫, dʒ]. The phones [f] and [v] are not considered sibilants by all linguists due to the fact that they do not display the same high frequencies as the aforementioned phonemes.