Assimilation
Assimilation is a process of alteration of speech sounds as a result of which one of the sounds becomes fully or partially similar to adjoining sound. (Assimilation is a type of coarticulation. It is the alteration of a speech sound to make it more similar to its neighbours.)
Assimilation happens because the organs of speech move into position for the second sound while making the first.
Types of assimilation can be distinguished according to the:
Direction;
Degree of completeness;
Degree of stability.
Direction of assimilation.
The influence of the neighbouring sounds in English can act in a progressive, regressive or reciprocal (double) direction.
When the articulatory features of the following sound are changed under the influence of the preceding sound, which remains unchanged, assimilation is called progressive.
l. The work of the vocal cords: a voiceless consonant + /l/, /r/, /w/. The sonorants are devoiced.
E.g.: please, try, quick, twenty, sweater, pray, price, tree, place.
When the following sound influences the articulation of the preceding one assimilation is called regressive.
1. The point of articulation:
/ t/, /d /, /n/, /l/, /s/, /z/ + / ð /, / θ /, /t/, /d/ + /r/
E.g.: tenth, in them, read this, all that, try.
The alveolar variants of the phonemes are replaced by their dental variants; postalveolar variants.
2. The point of articulation and the active organ of speech. In the words with the stressed prefix con- + /k/,/g/ - /n/ → / ŋ /.
The forelingual alveolar sound is replaced by the back-lingual velar sound.
E.g.: congress.
3. The lip position.
/k/, /g/, /t/, /s/, /d/ + /w/. The variants of the phonemes are replaced by their labialized variants.
E.g.: quick, twenty.
4. The manner of the production of noise:
a) loss of plosion:
/t/, /d/, /p/, /b/ /k/, /g/ + /t/, /d/, /p/, /b/, /k/, /g/.
E.g.: doctor, blackboard, bookcase. There is a complete loss of plosion of the first sound;
nasal plosion: /t/, /d/, /p/, /b/, /k/, /g/ + /n / , /m/. E.g.: curtain, student;
lateral plosion: /t/, /d/, /p/, /b/, /k/, /g/ + /l/. E.g.: plan, simple, table;
fricative plosion: /t/, /d/, /p/, /p/, /g/, /k/+ a fricative sound.
E.g.: sets, wants, besides, lamps, rugs, takes.
Reciprocal or double assimilation means complex mutual influence of the adjacent sounds.
Two adjacent consonants influence each other.
E.g.: twenty, try, please, sweater.
Degree of completeness.
According to its degree, assimilation can be complete and incomplete. Assimilation is called complete in the case the two adjoining sounds become alike or merge into one. It always takes place when the two sounds differ only in one articulatory feature.
E.g.: cupboard / 'kʌpbəd - 'kʌbəd/.
Assimilation is called incomplete when the likeness of the adjoining sounds is partial as the assimilated sounds retain its major articulatory features.
E.g.: the sonorants /w, l, r / are partially devoiced when preceded by the voiceless /p, t, k, s, f, θ/.
Degree of Stability.
Many assimilatory phenomena of older stages in the development of the language have become obligatory in modern English. They may or may not be reflected in spelling. In modern language obligatory assimilations are special allophonic variants characteristic of the natives’ speech.
Besides there are a lot of widely spread but non-obligatory cases of assimilation, which can be traced mainly at word boundaries. Non-obligatory assimilations are characteristic of fluent or careless speech and should be avoided by public speakers (lecturers, teachers, etc.).
Examples of more frequent changes.
t, d, n at the end of the word or syllable can assimilate to the place of articulation of the consonant at the beginning of the next syllable.
- n can become / m / before p, b, m.
ten men /tem men/
n can become /ŋ/ before k, g.
fine grade /faiŋ greid/
d can change to /b/ and /g/ respectively
red paint /reb peint/
bad guys /bæg gaiz/
It is also possible for t to change to /p/ and /k/ respectively, though a more frequent possibility is for t to be realized as a glottal stop when followed by plosives and constrictive consonants.
Eight boys /eı? boız/
In the same way s and z can change to // and / ʒ / respectively, but only before // or /j/ at the beginning of the next syllable.
This shape /ðı eıp/
These shoes /ði:ʒ u:z/
This unit /ðı 'ju:nıt/
As you see /æʒ ju si:/
Yod coalescence (or coalescent assimilation) is a process which changes t or d plus / j / into /t/ or /dʒ / respectively. Across word boundaries, in standard accents it mainly affects phrases involving you or your.
Let you out /let ju aʊt let u aʊt/
Would you try /wʊd ju traı wʊdʒ u traı/
Within a word these changes happen when vowel is weak.
Factual / 'fækt juəl 'fæktuəl /
Educate / 'ed ju keıt 'edʒukeıt/