Assimilation Rules

Assimilation Rules
Definition

From Latin assimilatio, meaning "to render similar“
A linguistic process by which a sound becomes similar to an adjacent sound.
Assimilation

Progressive Assimilation
If the phoneme changes to match the preceding phoneme, it is progressive assimilation.

Regressive Assimilation
If the phoneme changes to match the following phoneme, it is regressive assimilation.

Reciprocal Assimilation
If there is a mutual influence between the two phonemes, it is reciprocal assimilation.

Consonant Assimilation
In the case the two phonemes can fuse completely and give a birth to a different one. This is called a coalescence. The result of consonant assimilation is usually a geminate consonant.

Assimilation Rules
Example

Total Assimilation
“winter” :
/t/ ? [n] / [n] __
(meaning that /t/ becomes [n] in the environment after [n]).
“center” :
/t/ ? [n] / [n] __
(/t/ becomes [n] in the environment after [n]).

Partial Assimilation
“stopped” :
/d/ ? [t] / [p] __
(i.e. /d/ becomes [t] in the environment after [p].)
“picked” :
/d/ ? [t] / [k] __
(i.e. /d/ becomes [t] in the environment after [k].)

Progressive (or left-to-right) Assimilation
“dogs” :
/s/ ? [z] / [g] __
( the ending [s] is assimilated to [z] by the influence of the preceding voiced [g].)
“pubs” :
/s/ ? [z] / [b] __
( the ending [s] is assimilated to [z] by the influence of the preceding voiced [b].)

Regressive, or Anticipatory (or right-to-left) Assimilation
“miss you” :
[m'ISE]
/s/ ? [S] / __ [ j ] .
(the sound [s] in [mIs] is changed to [S] by the assimilation of the following palatal glide [ j ].)

Double Assimilation
“man” :
/A/ ? [A] / [m] __ [n]
(The [A] in /mAn/ is nasalized by its preceding [m] and its following [n].)

References
American English Phonetics
作者：孫淑惠 著
發行所：文鶴出版有限公司
“http://www.indiana.edu/~hlw/PhonProcess/assimilation.html”
“http://www.ielanguages.com/linguist.html”
“http://www.uni-assel.de/fb8/misc/lfb/html/text/8-4-1.html”