Guide to phonology

Phonological rules

All languages have sounds that change slightly (or sometimes dramatically) based on the effects of other phonemes around it. These are known as phonological processes. We express them in writing as phonological rules. In technical terms, it is a way of expressing when and where a phoneme changes into one of its allophones.

There are a few examples in English. My favourite is probably the writer/rider example. Note that the words writer and rider are identical in pronunciation, despite different spelling, different meaning, and despite the fact that they come from two obviously different root words: write and ride. The consonant in the middle of the words writer and rider is neither a /t/ or /d/, but a quick tap of the tongue behind the teeth. Linguists call this a tap, and its IPA symbol is /ɾ/. It turns out the tap occurs consistently in certain environments. It occurs between the words litre and leader, and cider and sighter. If a pattern like this can be established it can said to be a phonological rule: /t/ and /d/ turn into a tap in between two vowels. The notation looks like this

t → ɾ / V_V
d → ɾ / V_V

where → means 'turns into', / means 'in the environment of' and V mean any vowel. We can package the two rules into one:

{t,d} → ɾ / V_V

When a word goes through a phonological rule such as this one we can give it a "narrow" pronunciation in square brackets:

writer /ˈɹaɪtə/ [ˈɹaɪɾə]
rider /ˈɹaɪdə/ [ˈɹaɪɾə]

The "broad" pronunciation (between forward slashes) can be thought of as the abstract pronunciation of the word; it is what we think the pronunciation is until we consciously analyse it and ties back to the meaning of the word (including its root word) and perhaps to the spelling of the word too. Meanwhile the narrow pronunciation is what the mouth and tongue are actually doing.

Another English phonological rule is vowel nasalisation. The rule is: vowels turn into nasal vowels before nasal consonants. Example: sing /sɪŋ/ [sɪ̃ŋ]. Formally it is written

V → V[+nasal] / _N

where N means nasal consonant, and square brackets [+nasal] to can be used to add a property to a class of phonemes.

Phonological rules have implications for how words will change pronunciation based on what affixes get attached. For example, imagine in your constructed language you make up a rule that o → u / _C (/o/ turns into [u] before any consonant). Now imagine you decided the way to form past-tense verbs is to add a suffix -t to the end of verbs, and the way to form present-tense is to add nothing to the verb. Now imagine your word for want is rito /ˈrito/. Your phonological rule will affect the root word in the past-tense only:

Present-tense: rito /ˈrito/
Past-tense: rito + t /ˈritot/ [ˈritut]

Types of Consonants

Consonants are phonemes that are articulated with complete or partial closure of the vocal tract. They contrast with vowels, which are articulated with the vocal tract relatively open.

Consonants can be broken down into classes based on a matrix of 1) where in the mouth the tongue is placed to article the sound (place of articulation) and 2) how the sound is articulated from that place (manner of articulation). You can see this on the standard IPA chart.

Manners of articulation

Stops

Stops are probably the most common type of consonants. Examples in English are p, b, t, d, k, g, where the air-flow through the mouth is momentarily completely blocked, and then released. We can contrast stops with consonants that have a continuous air flow, like s, z, m and n.

"Stop" describes a manner of articulation. Manners of articulation can be performed at various different places in the mouth (place of articulation). Note that the only difference between /p/ and /t/ is that in /p/ the air flow is stopped at the momentary closure of the lips, and in /t/ the air flow is stopped with the tongue behind the teeth. Both have the same manner of articulation, but the place of articulation is different. There are other stops in the International Phonetic Alphabet that do not occur in English. For instance, Arabic has the stop whose place of articulation is way in the back of the throat, at the uvula. Its symbol is /q/ and might sound a little bit like an English "k" to untrained ears.

In phonological rule notation a capital S may be used to mean all stop consonants. Example: a > e /_S (/a/ turns into /e/ before any stop).

Nasal consonants

Nasal consonants are produced by allowing air to escape through the nose. In English they are /n/, /m/ and /ŋ/. In phonological rule notation a capital N may be used to mean all nasal consonants.

Fricatives

Fricatives are produced by forcing air through a narrow channel in the vocal tract, to create turbulent airflow. In English these include /s/, /z/, /f/, /v/, as well as /ʃ/ the sounded represented by ‘sh’, /ʒ/ as in pleasure, /θ/ as in thin and /ð/ as in this. In phonological rules they may be represented as F.

Affricates

Affricates are a combination of a stop and fricative in short succession. The best example in English is the ‘ch’ sound, which is actually a combination of a /t/ and a /ʃ/, resulting in /ʧ/.

Flap or tap

Flaps or taps are similar to stops but more brief. An example is /ɾ/ in rider.

Trills

Trills are produced with the tongue vibrating against some part of the mouth. A Spanish ‘r’ is a classic example of a trill, however they do not occur in most dialects of English.

Approximants

Approximants in English include /w/ as in water, /j/ as in you, and /ɹ/ as in ready. They are defined as phonemes where the vocal tract narrows at some place of articulation, enough to not be a vowel but not enough to create turbulent airflow such as a fricative. In phonological rules they may be represented as A.

Laterals

Laterals are various L-like consonants. In English the only lateral is /l/, but a few other types exist. In phonological rules they may be represented as L.

Places of articulation

Bilabial

Bilabial means ‘two lipped’ in Latin. These are consonants that are produced by closing lips together is some way or another. In English they include stops /p/ and /b/, and the nasal /m/. In phonological rules they may be represented as P.

Labio-dental

Labio-dental consonants are with the upper teeth touching the lower lip. In English they include /f/ and /v/.

Dentals and alveolars

Dental consonants are articulated with the tongue against the upper teeth, consonants such as /t/, /d/, /n/, /s/, /z/, and /l/. However in some languages "dentals" are actually produced slightly further back in mouth at the alveolar ridge. For this reason linguists may choose to represent dentals with diacritic symbols (t̪ d̪ n̪ s̪ z̪) to disambiguate them from the alveolar location. English only has alveolar consonants.

Dental consonants are sometimes further broken down into interdental, where the tongue is between upper and lower teeth: the ‘th’ sounds in English are interdental, /θ/ as in thin and /ð/ as in this.

Postalveolar

Postalveolar consonants are articulated with the tongue slightly further behind where alveolar consonants are produced. These include /ʃ/ ‘sh’, /ʒ/ as in pleasure, as well as affricates /ʧ/ and /ʤ/.

Palatal

Palatal consonants are articulated with the tongue against the middle part of the roof of the mouth (hard palate). In English the only palatal consonant is /j/ as in you.

Velar

Velar consonants are articulated with the back part of the tongue against the back part of the roof of the mouth (soft palate). In English these are /k/, /g/ and /ŋ/ as in ‘ng’ sounds. In phonological rules they may be represented as K.

Voicing

Voicing is best illustrated by the difference between phonemes /s/ and /z/. These two phonemes have the exact same manner and place of articulation; both fricatives in the alveolar position. So how do they differ? In producing these sounds you will notice your vocal chords vibrating during the articulation of the /z/. The term "voicing" refers to whether the vocal chords vibrate during the production of a phoneme. All phonemes have a voiced and voiceless counterpart, although not all of them maybe the present in a given language. They may be represented in phonological rules as C[+voice] and C[-voice]. The following tables shows voiced/voiceless pairs in English: