Phonetics and Phonology

by Heidrun Dorgeloh

The two primary linguistic disciplines concerned with speech sounds - those sounds that are used by humans to communicate - are phonetics and phonology. Both areas are mutually dependent. Phonetics describes the concrete, physical form of sounds (how they are produced, heard and how they can be described), while phonology is concerned with the function of sounds, that is with their status and inventory in any given language.

Phones and Phonetics

The two basic tasks of phonetics are the transcription and the classification of sounds, also called phones in this context. The phone is therefore the basic unit of phonetics and it refers to the concrete sound substance as such. In the area of articulatory phonetics this substance is described on the basis of the articulatory properties. These refer to the human vocal tract (or to the speech organs), illustrated below, and are used to describe and classify sounds. By contrast, acoustic and auditory phonetics deal with the characteristics of sound waves and how they are perceived by the human ear.

Phones are represented by placing brackets around the transcription ([da:ns]/[dæns] for dance in British and American English)). The usefulness of a transcription system (a phonetic alphabet) is particularly plausible in a language such as English, where pronounciation and and spelling often diverge substantially (cp. see – sea on the one hand, and through and though, on the other). There are various transcription models, such as the IPA (International Phonetic Alphabet); for the transcription of English, several, slightly differing systems have evolved, all of them following in some way the original model of the phonetician Daniel Jones.

Classification of sounds

Traditionally, sounds are classified into consonants and vowels. Consonants are sounds that are produced with a major obstruction in the mouth cavity. For example, in the case of [t] (Fig. 1), there is direct contact between the tip of the tongue (active articulator) and the alveolar ridge (passive articulator), so that the airflow coming from the lungs can leave the mouth cavity only when the obstruction is removed:

Fig. 1. consonant [t]

Vowels are sounds that are produced without such obstruction. For example, in the case of [i:] (Fig. 2), there is a gap within the mouth that is determined by the position of the tongue, and the airflow can escape relatively freely: 

Fig. 2. vowel [i]

Another difference between consonants and vowels is that vowels are generally voiced, i.e. the vocal cords are set vibrating by the outgoing airflow. Consonants, by contrast, can be voiced or voiceless: The vocal cords are either far apart and do not vibrate, as in fan, or they are relatively closed and vibrate as in van (Fig. 3).
Fig. 3. Vibration of vocal cords in the articulation of voiced sounds

Classification of consonants

Factors relevant for the classification of consonants include the manner of articulation, the place of articulation, and voicing. With regard to the manner of articulation, English consonants can be classified into plosives, fricatives, affricates, nasals, liquids, and semi-vowels.

Plosives are consonants that are made up by completely blocking the airflow. The production of plosives involves three stages:

1. a direct contact between the active and the passive articulator forming a complete obstruction to the airflow;
2. the compression of air behind the obstruction; and
3. the release of the compressed air in the form of an “explosion” (hence the term plosive).

There are six plosives in English: bilabial [p] and [b], alveolar [t] and [d], and velar [k] and [g].

Bilabial plosives [p] and [b] are produced with both lips pressed together. The active articulator is the lower lip; the passive articulator is the upper lip. The soft palate is raised and the air coming into the mouth stops for some time and then breaks the obstruction with a slight explosion. In the case of [b], the vocal cords are vibrating

Fig. 4. bilabial posives [p] and [b]

Alveolar plosives [t] and [d] are produced with the tip of the tongue firmly pressed against the (middle part of the) alveolar ridge. The active articulator is the tip of the tongue; the passive articulator is the alveolar ridge. The tip of the tongue makes firm contact with the alveolar ridge. The air is trapped for a short time and then breaks the obstruction with a slight explosion. In the case of [d], the vocal cords are vibrating:

Fig. 5. alveolar plosives [t] and [d]

Velar plosives [k] and [g] are articulated with the back of the tongue against the soft palate. The active articulator is the back of the tongue; the passive articulator is the soft palate. The back of the tongue makes firm contact with the soft palate. The air is trapped for a short time and then breaks the obstruction with a slight explosion. In the case of [g], the vocal cords are vibrating:

Fig. 6. velar plosives [k] and [g]

Fricatives are consonants that are produced by impeding, but not completely blocking the airflow, i.e., there is a narrow gap between the active and the passive articulator along which the airflow can leave the oral cavity. There are nine fricatives in English: labio-dental [f] and [v], interdental [θ] and [ð], alveolar [s] and [z], palate-alveolar [ʃ] and [ʒ], and glottal [h].
Fig. 7. labio-dental fricatives [f] and [v]

The lower lip is very close to the edge of the upper front teeth, thus forming an incomplete obstruction. When the air goes through the narrowing it causes slight friction (hence the term fricative). For [f] the vocal cords do not vibrate; there may be some vibration accompanying [v] when it occurs in word initial position as in e.g. vast or between vowels as in e.g. never.

Fig. 8. interdental fricatives [θ] and [ð]

The tip of the tongue is either close to the edge of the upper teeth or slightly projected between the teeth. For [θ] the friction is as strong as for [f], for [ð] it is gentler. For [θ] the vocal cords do not vibrate; they vibrate for [ð] when it occurs in word initial position, before a vowel or in intervocalic positions. E.g. that, rather, etc.

Other fricatives are produced with different places of articulation: For the alveolar fricatives [s] and [z], the tip of the tongue is close to the alveolar ridge. The teeth are very close together. The friction for [s] is strong, even stronger than for [θ]. For [s] the vocal cords do not vibrate; they vibrate for [z] when it occurs before vowels or in intervocalic positions. E.g. zone, easy, etc.

Fig. 9. alveolar and palate-alveolar fricatives [s], [z], [ʃ] and [ʒ]

For [ʃ] and [ʒ], the tip of the tongue is close to the back part of the alveolar ridge forming a flat narrowing. The front part of the tongue is raised towards the hard palate forming the front secondary focus. The friction for [ʃ] is strong, stronger than for [f] and [θ]. For [ʃ] the vocal cords do not vibrate; they vibrate for [ʒ] when it occurs before vowels. E.g. pleasure, etc.
Fig. 10. glottal fricative [h]

It is produced with the voiceless expulsion of air from the lungs with the mouth and tongue already in position for the following vowel.

Affricates are sounds that are similar to both plosives and fricatives: The tip of the tongue touches the back part of the teeth ridge, the front part of the tongue is raised towards the hard palate. The air is trapped for a short time because of a complete obstruction between the tip of the tongue and the teeth ridge, then the obstruction is released slowly and the friction is heard. The voiceless affricate is [tʃ] as in chain, whereas [dʒ], as in jelly, is voiced.
Nasals are consonants which, like plosives, are produced by completely blocking the airstream. But there is an important difference: The airflow escapes through the nasal cavity (hence the term nasals). There are three nasal consonants in English: bilabial [m], alveolar [n], and velar [ŋ]:
Fig. 11. bilabial nasal [m]

The lips are firmly kept together forming the complete obstruction. The active articulator is the lower lip; the passive articulator is the upper lip. The soft palate is lowered and the air escapes through the nasal cavity. The vocal cords are vibrating.

Fig. 12. alveolar nasal [n]

The tip of the tongue is pressed against the alveolar ridge forming the complete obstruction. The active articulator is the tip of the tongue, and the passive articulator is the alveolar ridge. The soft palate is lowered and the air escapes through the nasal cavity. The vocal cords are vibrating.
 
Fig. 13. velar nasal [ŋ]

The back of the tongue is pressed to the soft palate forming the complete obstruction. The active articulator is the back of the tongue, and the passive articulator is the soft palate. The soft palate is lowered and the air escapes through the nasal cavity. The vocal cords are vibrating.

Liquids include alveolar [l] and post-alveolar [r].
Fig. 14. alveolar [l]

The tip of the tongue is in firm contact with the alveolar ridge forming the complete obstruction. The active articulator is the tip of the tongue, and the passive articulator is the alveolar ridge. The sides of the tongue are lowered and the air can pass between them. The vocal cords are brought together and are vibrating.

Fig. 15. post-alveolar [r]

The tip of the tongue is held in a position near to but not touching the back part of the alveolar ridge. The soft palate is raised and the air flows quietly between the tip of the tongue and the hard palate. The front part of the tongue is low and the back is rather high so that the tongue has a curved shape. The vocal cords are vibrating.

Semi-glides or glides include bilabial [w] and palatal [j]: [w], as in why, starts out with the lips firmly rounded, these articulators then moving away (= gliding) from the narrowing in the mouth. When articulating [j], as in you, the front part of the tongue is first raised towards the hard palate, then the soft palate is raised and the air goes along the central part of the tongue. The vocal cords are kept together and are vibrating.

The reason why these sounds are called semi-vowels is thus their manner of articulation: Like true vowels, semi-vowels are produced without a major obstruction, i.e., there is a wide gap between the active and the passive articulator, so that the airflow can escape relatively freely from the mouth. However, unlike true vowels, semi-vowels never form the nucleus of a syllable (e.g., week, yellow) and are therefore usually considered consonants.

Classification of vowels

Depending on the height of the tongue, vowels can be classified into high, low, and mid vowels:

1. When the front or the back of the tongue is raised towards the roof of the mouth, the vowel is called high, this is the case, e.g., in pill, meet, look, or soon.
2. When the front or the back of the tongue is as low as possible, the vowel is called low, as, e.g., in land, star, or dog.
3. When the tongue occupies the position intermediate between the high and the low one, the vowel is called mid, e.g. in get, or the unstressed [ə] in about.

Depending on the active articulator, vowels are classified into front, back, and central vowels:

1. When the front part of the tongue is raised towards the hard palate, the vowel is called front, e.g. in meet, get, or land.
2. When the back part of the tongue is raised towards the soft palate, the vowel is called back, as in star, dog, law, or soon.
3. When the front part of the tongue is raised towards the back part of the hard palate, the vowel is called central, e.g. in about, much, or nurse.

These high-low and front-back dimensions of vowel articulation are also referred to as vowel quality. To illustrate how the articulatory properties of vowels relate to each other, a vowel chart is commonly used as a reference system. The chart below (adapted from Kortmann (2006: 68)) describes the basic vowel qualities of most standard varieties of English together with their phonetic transcription.

As can be seen from this chart, some vowels do not only differ qualitatively, but also quantitatively (as indicated by the colon as the diacritic for length). Long as opposed to short vowels also differ by being tense as opposed to lax:

1. Tense vowels are produced with a deliberate, accurate, maximally distinct gesture that involves considerable muscular effort. Tense vowels are either long vowels (e.g. [i:] in meet) or diphthongs (e.g. [eI] in say).
2. Non-tense (or lax) vowels are produced rapidly and are therefore short (e.g. [I] in pill).

Diphthongs

The vowels described so far have all been monophthongs, in contrast to the diphthongs (or gliding vowels), during the production of which the tongue moves from one position to another. Examples are in day, fight, and oil and so and sow for the so-called closing diphthongs, while centring diphthongs occur, for example, in bare, beer, and sure.

Phonemes and phonology

Phonemes, in contrast to phones, are defined by their function within the language system (langue). This function is basically one of meaning differentiation, although other functions of phonic means, such as an expressive function of vowel lengthening (That was coooooool), are also possible. All sounds, however, which have a meaning-differentiating function within a given language are considered phonemes within that language system; these are abstract, idealized units within our minds or parts of our model of a language that we design; in language use (parole) phonemes are always realized as phones.

The test for these smallest distinctive units of a given language system is the minimal pair test, i.e. when a difference in sound structure also causes a shift in meaning. An example is [k] in cable and [t] in table, which therefore constitute phonemes of English, indicated by the notation /k/ and /t/. Note, however, that we are dealing with the actual sound structure here, not with spelling, so tea/he are a minimal pair, while see/sea are not. Also, minimal pairs are only pairings that differ in exactly one segment; so, pin and tin, or tin and ten, are minimal pairs, while pin and ten would be not.

Allophones

Some sound differences do not differentiate meaning, as in the pronunciation of /l/ in the words lip and pill. While the difference may be only slight (you may try to keep track of where you place the tip of your tongue), from a phonetic point of view the two realizations of /l/ have to be considered two phones, but not two phonemes. They are called clear and dark /l/ and are two allophones of the phoneme /l/ in English.

Distribution of allophones

In contrast to phonemes, allophones do not occur in minimal pairs, which means they either never occur in the same environment (complementary distribution), as in the case of clear and dark /l/, or they occur in free variation. For example, voiceless plosives at the end of a syllable or word are sometimes aspirated (if deep is pronounced [di:ph]), but they may just as well not be (if deep is pronounced [di:p]). The decisive difference between phonemes and their allophones is that the variants of a phoneme do not differentiate meaning, and therefore the sound difference does not constitute a relevant phonetic feature.

Phonological systems

The phonology of a language is also the inventory of its phonemes, i.e. the sum of all those sounds that show distinctive (i.e. meaning-differentiating) phonetic differences. RP as the standard (British) English sound system, for example, has

• 24 consonants,
• 12 vowels, and
• 8 diphthongs

but it has many more allophones (such as clear and dark /l/, or the aspirated plosives). By contrast, this table shows the phoneme inventory of Standard Mandarin, the official language of China: As can be seen, one major difference to English is that Standard Mandarin lacks the voiced bilabial, alveolar and velar plosives /b/, /d/ and /g/, while it has the aspirated versions of the consonants pʰ, tʰ, kʰ as distinct phonemes. In other words, a difference (aspiration) that does not distinguish meaning in English and is thus a redundant articulatory feature constitutes a distinctive feature in Mandarin Chinese, while another one (the voicing of plosives) is distinctive in English (i.e. it distinguishes meaning), but not in Chinese.

Syllables

Phonology does not only describe a system of sounds in isolation, but it also deals with the rules and restrictions that hold for their combinations. This branch of phonology is called phonotactics. Phones combine into the syllable, which is essentially a vowel with optional consonants clustered around it. The vowel forms the nucleus of a syllable, with the onset in front of it and the coda behind it. Depending on whether there is a coda or not, a syllable can be described as either closed or open. The basic form of the English syllable is (CCC) V (CCCC), i.e. I, spray, or texts are all examples of one syllable but of different complexity.

Prosody

Prosody belongs to the domain of suprasegmental phonology in that it describes phenomena extending over more than one phoneme. The phenomena that belong here are stress, rhythm, and intonation. While stress can be word or sentence stress, rhythm and intonation occur in phrases and sentences. Intonation is described by reference to pitch (tones); different levels of pitch are used to express a wide range of meanings: for example, we use the difference between a falling and a rising pitch pattern in statements and questions.

Connected Speech

The phonological changes that occur when language is used in natural utterances are described as features of connected speech. The most important ones are:

• assimilation, i.e. when neighbouring sounds become more alike (as in IM-possible, in contrast to IN-decent)
• elision, i.e. the loss of sounds (as in Chris(t)mas or san(d)wich)
• intrusion and linking (as in law(r) and order).

The most important feature of connected speech, however, is the occurrence of weak forms, which is the result of the occurrence of stress in connected speech. English has the property of being a stress-timed language, which means there is a tendency for stressed syllables to occur at fairly equal intervals. As a result, in unstressed syllables vowel quality tends to be weakened, mostly to the schwa [ə], but the total omission of vowels (as it frequently happens in contractions, such as isn’t, she’s) is also possible, particularly in the case of function words (auxiliaries, pronouns, prepositions, conjunctions).