A general term in phonetics for the process by which a speech sound becomes similar or identical to a neighboring sound. In the opposite process, dissimilation, sounds become less similar to one another.
For some varieties of assimilation in English, see Examples and Observations, below.
International Phonetic Alphabet (IPA)
Segment and Suprasegmental
From the Latin, "make similar to"
Examples and Observations:
"Assimilation is the influence of a sound on a neighboring sound so that the two become similar or the same. For example, the Latin prefix in- 'not, non-, un-' appears in English as il-, im-. and ir- in the words illegal, immoral, impossible (both m and p are bilabial consonants), and irresponsible as well as the unassimilated original form in- in indecent and incompetent. Although the assimilation of the n of in- to the following consonant in the preceding examples was inherited from Latin, English examples that would be considered native are also plentiful. In rapid speech native speakers of English tend to pronounce ten bucks as though it were written tembucks, and in anticipation of the voiceless s in son the final consonant of his in his son is not as fully voiced as the s in his daughter, where it clearly is [z]."
(Zdenek Salzmann, Language, Culture, and Society: An Introduction to Linguistic Anthropology. Westview, 2004)
"Features of adjacent sounds may combine so that one of the sounds may not be pronounced. The nasal feature of the mn combination in hymn results in the loss of /n/ in this word (progressive assimilation), but not in hymnal. Likewise, the alveolar (upper gum ridge) production of nt in a word such as winter may result in the loss of /t/ to produce a word that sounds like winner. However, the /t/ is pronounced in...