Phones and Allophones
Phonemes are not physical sounds. They are abstract mental representations of the phonological units of a language. Phones are considered to be any single speech sound of which phonemes are made. Phonemes are a family of phones regarded as a single sound and represented by the same symbol. The different phones that are the realization of a phoneme are called allophones of that phoneme. The use of allophones is not random, but rule-governed. No one is taught these rules as they are learned subconsciously when the native language is acquired. To distinguish between a phoneme and its allophones, I will use slashes // to enclose phonemes and brackets [ ] to enclose allophones or phones. For example, and [ĩ] are allophones of the phoneme /i/; and [Iɪ̃] are allophones of the phoneme /I/.
If two sounds are allophones of the same phoneme, they are said to be in complementary distribution. These sounds cannot occur in minimal pairs and they cannot change the meaning of otherwise identical words. If you interchange the sounds, you will only change the pronunciation of the words, not the meaning. Native speakers of the language regard the two allophones as variations of the same sound. To hear this, start to say the word cool (your lips should be pursed in anticipation of /u/ sound), but then say kill instead (with your lips still pursed.) Your pronunciation of kill should sound strange because cool and kill are pronounced with different allophones of the phoneme /k/.
Nasalized vowels are allophones of the same phoneme in English. Take, for example, the sounds in bad and ban. The phoneme is /Ã¦/, however the allophones are [Ã¦] and [Ã¦̃]. Yet in French, nasalized vowels are not allophones of the same phonemes. They are separate phonemes. The words beau [bo] and bon [bÃµ] are not in complementary distribution because they are minimal pairs and have contrasting sounds. Changing the sounds changes the meaning of the words. This is just one example of differences between languages.
Assimilation: sounds become more like neighboring sounds, allowing for ease of articulation or pronunciation; such as vowels are nasalized before nasal consonants
- Harmony: non-adjacent vowels become more similar by sharing a feature or set of features (common in Finnish)
- Gemination: sound becomes identical to an adjacent sound
- Regressive Assimilation: sound on left is the target, and sound on right is the trigger
Dissimilation: sounds become less like neighboring sounds; these rules are quite rare, but one example in English is [fɪfθ] becoming [fɪft] (/f/ and /θ/ are both fricatives, but /t/ is a stop)
Epenthesis: insertion of a sound, e.g. Latin "homre" became Spanish "hombre"
- Prothesis: insertion of vowel sound at beginning of word
- Anaptyxis: vowel sound with predictable quality is inserted word-internally
- Paragoge: insertion of vowel sound at end of word
- Excrescence: consonant sound inserted between other consonants (also called stop-intrusion)
Deletion: deletion of a sound; e.g. French word-final consonants are deleted when the next word begins with a consonant (but are retained when the following word begins with a vowel)
- Aphaeresis: vowel sound deleted at beginning of word
- Syncope: vowel sound is deleted word-internally
- Apocope: vowel sound deleted at end of word
Metathesis: reordering of phonemes; in some dialects of English, the word asked is pronounced [Ã¦ks]; children's speech shows many cases of metathesis such as aminal for animal
Lenition: consonant changes to a weaker manner of articulation; voiced stop becomes a fricative, fricative becomes a glide, etc.
Palatalization: sound becomes palatal when adjacent to a front vowel Compensatory Lengthening: sound becomes long as a result of sound loss, e.g. Latin "octo" became Italian "otto"
(Source:Victoria Fromkin and Robert Rodman)
P-2 : Assimilation in English, Writing Rules and Syllable Structure