Phoneme as a unit of language

Phonology
The branch of phonetics that studies the linguistic function of consonant and vowel sounds, syllabic structure, word accent and prosodic features, such as pitch, stress and tempo

Function
discriminatory function
→ the role of the various elements of the language in the distinguishing of one sequence of sounds, such as a word or a sequence of words, from another of different meaning.
function of phonetic units
→ their role in the formation of syllables, words, phrases and even texts.

History
I.A.Baudouin-de-Courtenay
introduced functional or social aspect of phonetic phenomena
N.S.Trubetskoy
declared phonology to be a linguistic science
limited articulatory and acoustic phonetics to anatomy, physiology and acoustics only.
This conception is shared by many foreign linguists → investigate the material form and the function of oral speech units separately.

Soviet linguists
language being the man's medium of thought can exist only in the material form of speech sounds
→ phonology a branch of phonetics that investigates its most important social aspect.

“Sound”
can be interpreted in two rather different ways.
[t] and [d] are two different sounds
[t] – fortis and [d] – lenis
tie - die, seat - seed
[t] in let us and [t] in let them → the two sounds are also not the same,
[t] of let us is alveolar, while the [t] of let them is dental.

“Sound”
In both examples the sounds differ in one articulatory feature only
in the second case the difference between the sounds has functionally no significance.
It is perfectly clear that the sense of "sound" in these two cases is different.

"phoneme" is used to mean "sound" in its contrastive sense
"allophone" is used for sounds which are variants of a phoneme:
they usually occur in different positions in the word (i.e. in different environments) and hence cannot contrast with each other, nor be used to make meaningful distinctions.

Phoneme
a functional, material and abstract unit (L.V. Shcherba)
a dialectical unity of these aspects because they determine one another and are thus interdependent (V.A.Vassilyev)

Phoneme
a minimal abstract linguistic unit realized in speech in the form of speech sounds opposable to other phonemes of the same language to distinguish the meaning of morphemes and words.

Phoneme
from the point of view of its three aspects:
functional,
material,
abstract

Firstly,
the phoneme is a functional unit:
discriminatory function
the role of the various components of the phonetic system → in distinguishing one morpheme from another, one word from another or also one utterance from another.

The distinctive function
The opposition of phonemes in the same phonetic environment differentiates the meaning of morphemes and words: e.g. said – says, sleeper – sleepy, bath – path, light – like.
Sometimes the opposition of phonemes serves to distinguish the meaning of the whole phrases: He was heard badly - He was hurt badly.

Secondly,
the phoneme is material, real and objective → it is realized in speech in the form of speech sounds, its allophones.
The phonemes constitute the material form of morphemes
↓ ↓
constitutive function

Thirdly,
the phoneme is a material and objective unit as well as an abstract and generalized one at the same time
the use of the right allophones and other phonetic units facilitates normal recognition
↓ ↓
recognitive function

Types of allophones and the main features of the phoneme
The sets of speech sounds → the allophones belonging to the same phoneme
are not identical in their articulatory content
though there remains some phonetic similarity between them.

English phoneme [d]
When not affected by the articulation of the preceding or following sounds [d] is a plosive, forelingual apical, alveolar, lenis stop: door, darn, down, In this case the consonant [d] is called the principal allophone.
The allophones which do not undergo any distinguishable changes in the chain of speech are called principal.

English phoneme [d]
At the same time there are quite predictable changes in the articulation of allophones that occur under the influence of the neighbouring sounds in different phonetic situations. Such allophones are called subsidiary.

English phoneme [d]
[d] is slightly palatalized before front vowels and the sonorant [j], e.g. deal, day, did, did you
[d] is pronounced without any plosion before another stop, e.g. bedtime, bad pain, good dog
[d] it is pronounced with the nasal plosion before the nasal sonorants [n] and [m], e.g. sudden, admit, could not, could meet;
the plosion is lateral before the lateral sonorant [l], e.g. middle, badly, bad light.

[d] becomes post-alveolar followed by [r], e.g. dry, dream;
[d] becomes dental followed by the interdental [θ], [ð], e.g. breadth, lead the way, good thing.
When [d] is followed by the labial [w] it becomes labialized, e.g. dweller.
In the initial position [d] is partially devoiced, e.g. dog, dean; in the intervocalic position or when followed by a sonorant it is fully voiced, e.g. order, leader, driver; in the word-final position it is voiceless, e.g. road, raised, old.

Consequently, though allophones of the same phoneme possess similar articulatory features they may frequently show considerable phonetic differences.

Allophones
are arranged into functionally similar groups → groups of sounds in which
the members of each group are not opposed to one another,
are opposable to members of any other group to distinguish meanings in otherwise similar sequences.

Allophones
Consequently allophones of the same phoneme never occur in similar phonetic contexts, they are entirely predictable according to the phonetic environment,
↓ ↓
carry no useful information
they cannot differentiate meanings

English phoneme [l]
the dark [ł] occurs following a vowel as in pill, cold, but it is not found before a vowel
whereas the clear [l] only occurs before a vowel, as in lip, like.
↓ ↓
These two vowels cannot contrast with each other in the way that [I] contrasts with [r] in lip - rip or lake - rake
there are no pairs of words which differ only in that one has [ł] and the other - [l].

The function of phonemes is to distinguish the meaning of morphemes and words.
Native speakers abstract themselves from the difference between the allophones of the same phoneme because it has no functional value
↓ ↓
do not realize that [d] is alveolar in dog, in dry it is post alveolar, in breadth it is dental

Allophones of each phoneme
possess a bundle of distinctive features, that makes this phoneme functionally different from all other phonemes of the language concerned.

This functionally relevant bundle of articulatory features is called the invariant of the phoneme.
Neither of the articulatory features that form the invariant of the phoneme can be changed without affecting the meaning.

All the allophones of the phoneme [d]
are occlusive, forelingual, lenis.
If occlusive articulation is changed for constrictive one →
[d] will be replaced by [z]
breed - breeze, deal - zeal

[d] will be replaced by [g] if the forelingual articulation is replaced by the backlingual one,
dear – gear, day- gay
The lenis articulation of [d] cannot be substituted by the fortis one because it will also bring about changes in meaning,
dry - try, ladder - latter, bid - bit.

That is why it is possible to state that occlusive, forelingual and lenis characteristics of the phoneme [d] are generalized in the mind of the speaker into what is called the invariant of this phoneme.

Distinctive or relevant articulatory features
To extract relevant feature of the phoneme we have to oppose it to some other phoneme in the same phonetic context.
If the opposed sounds differ in one articulatory feature and this difference brings about changes in the meaning of the words the contrasting features are called relevant.

the words port and court differ in one consonant only ↓
initial consonant [p] and [k]
Both sounds are occlusive and fortis, the only difference being that [p] is labial and [k] is backlingual.
↓ ↓
labial and backlingual articulations are relevant in the system of English consonants

Non-distinctive, irrelevant or redundant articulatory features
do not serve to distinguish meaning
an aspirated [p] ↔ a non-aspirated [p]
↓ ↓
aspiration is a non-distinctive feature of English consonants

Mistakes in the articulation
L.V. Shcherba:
pronunciation errors →
phonological
phonetic

Phonological mistake
If an allopnone of some phoneme is replaced by an allophone of a different phoneme → the meaning of the word is inevitably affected.
the vowel [i:] in the word beat becomes slightly more open, more advanced or is no longer diphthongized
beat → quite a different word bit.