Assimilation (phonology)

In phonology, assimilation is a sound change in which some phonemes (typically consonants or vowels) change to become more similar to other nearby sounds. This process is common across languages and can happen within a word or between words. For example, in English "handbag" (), the often shifts to in rapid speech, becoming , because and are both bilabial (produced with both lips), and their places of articulation are similar.

It occurs in normal speech but is more frequent in faster speech. Sometimes the change is accepted as canonical, and can even become recognized in standard spelling: implosion pronounced with , composed of in- + -plosion (as in explosion).

Sound segments typically assimilate to a following sound, but they may also assimilate to a preceding one. Assimilation most commonly occurs between immediately adjacent sounds but may occur between sounds separated by others. For example, in "handbag", the is sometimes elided (omitted), which causes the to assimilate to before the .

Assimilation can be synchronic, an active process in a language at a given point in time, or diachronic, a historical sound change—for instance, "cupboard", historically a compound of "cup" () and "board" (), is now pronounced , with the original almost never used.

A related process, coarticulation, includes changes like vowels nasalizing (taking on a nasal sound) before nasal consonants () due to premature soft palate (velum) lowering, or labializing (lips rounding) as in "boot" () or "ball" in some accents. This article describes both processes under the term assimilation.

Concept

The physiological or psychological mechanisms of coarticulation are unknown, and coarticulation is often loosely referred to as a segment being "triggered" by an assimilatory change in another segment. In assimilation, the phonological patterning of the language, discourse styles and accent are some of the factors contributing to changes observed.

Assimilation are usually categorized by two properties: assimilations may be

between adjacent segments; or
between segments separated by one or more intervening segments,

and they may be

changes made in reference to a preceding segment; or
changes made in reference to a following segment,

resulting in four possible configurations.

Although all four occur, changes in regard to a following adjacent segment account for most assimilatory changes and virtually all of the regular ones. Similarly, assimilations to an adjacent segment are far more frequent than assimilations to a nonadjacent one. Those radical asymmetries might contain hints about the mechanisms involved, but they are not obvious.

If a sound changes with reference to a following segment, it is traditionally called "regressive assimilation". Changes with reference to a preceding segment are traditionally called "progressive". Many people find those terms confusing, as they may seem to indicate the opposite of the intended meaning. Accordingly, a variety of alternative terms have arisen, not all of which avoid the problem of the traditional terms. Regressive assimilation is also known as right-to-left, leading, or anticipatory assimilation. Progressive assimilation is also known as left-to-right, preseveratory, preservative, lagging, or lag assimilation. The terms anticipatory and lag are used here.

Occasionally, two sounds (invariably adjacent) may influence each other in reciprocal assimilation. When such a change results in a single segment with some of the features of both components, it is known as coalescence or fusion.

Assimilation occurs in two different types: complete assimilation, in which the sound affected by assimilation becomes exactly the same as the sound causing assimilation, and partial assimilation, in which the sound becomes the same in one or more features but remains different in other features, such as place of articulation. Tonal languages may exhibit tone assimilation; also see tone sandhi. Sign languages also exhibit assimilation when the characteristics of neighbouring cheremes may be mixed.

Examples

Anticipatory assimilation to an adjacent segment

Anticipatory assimilation to an adjacent segment is the most common type of assimilation by far and typically has the character of a conditioned sound change: it applies to all or part of the lexicon.

For example, in English, the place of articulation of nasals assimilates to that of a following stop (handkerchief is pronounced , handbag in rapid speech is pronounced ).

In Italian, voiceless stops assimilated historically to a following :

Latin "eight" > It.
Latin "bed" >
Latin – pronounced "under" >

Italian and are examples of historical restructuring: and no longer contain pronounced , and is no longer the structure subject to the partial assimilation of devoicing of and full assimilation to produce . Over time, phonetic as a frequent assimilation of and was rather reinterpreted as reflecting . The structural sequence is now all but absent in Italian since all items in popular speech have undergone the same restructuring: . On the rare occasion that Italian is encountered, however, the same assimilation that triggered the restructuring can occur at the phonetic level. For example, the medical term 'stroke', a relatively recent direct borrowing from Latin, is usually pronounced in deliberate speech, but is frequent in more casual registers.

Latin > Italian , pronounced either or

Affrication in English

There has been a notable change recognized across a variety of English dialects regarding the pronunciation of the and consonant clusters. Starting around the mid-20th century, the alveolar stop in has slowly been replaced by a post-alveolar affricate instead, resulting in the all-postalveolar consonant clusters and . This phenomenon also occurs in , resulting in the all-postalveolar consonant cluster . The affrication of has been seen in American English, British English, Australian English, and New Zealand English.

Anticipatory assimilation at a distance

For consonants, anticipatory assimilation at a distance is rare and usually a non-systematic irregular development in the history of a specific word.

Standard Slovene (a toponym) > Slovene dialect
Slovene > (a mountain ridge)

There are two major types of coalescence: reductive and unreductive. Reductive coalescence is the type of coalescence in which sound segments are reduced after fusion is made. For example, in Xhosa, becomes (side). The segment in the first form reduces to . On the other hand, non-reductive coalescence have no reduction in sound segments even though there is evidence of fusion. For example, in Shona, (they sell) becomes (to sell). There, the original sound does not reduce with respect to sound segments even though the rising tone on the vowels in the coalesced form indicates the fusion of to the vowels.

Notes

References

Citations

Sources

Crowley, Terry. (1997) An Introduction to Historical Linguistics. 3rd edition. Oxford University Press.