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Assimilation (phonology)
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| Sound change and alternation |
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| Fortition |
| Dissimilation |
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" (/ˈhændbæɡ/), the [n] often shifts to [m] in rapid speech, becoming /ˈhæmbæɡ/, because [m] and [b] 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 [m], composed of in- + -plosion (as in explosion).
Sound segments typically assimilate to a following sound,[note 1] but they may also assimilate to a preceding one.[note 2] Assimilation most commonly occurs between immediately adjacent sounds but may occur between sounds separated by others.[note 3] For example, in "handbag," the [d] is sometimes elided (omitted), which causes the [n] to assimilate to [m] before the [b].
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" (/kʌp/) and "board" (/bɔːrd/), is now pronounced /ˈkʌbərd/, with the original /ˈkʌpbɔːrd/ almost never used.[note 4]
A related process, coarticulation, includes changes like vowels nasalizing (taking on a nasal sound) before nasal consonants (/n, m, ŋ/) due to premature soft palate (velum) lowering, or /b/ labializing (lips rounding) as in "boot" ([bʷuːt̚]) or "ball" [bʷɔːɫ] in some accents. This article describes both processes under the term assimilation.
Concept
[edit]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.
There are four configurations found in assimilations:
- Between adjacent segments.
- Between segments separated by one or more intervening segments.
- Changes made in reference to a preceding segment
- Changes made in reference to a following segment
Although all four occur, changes in regard to a following adjacent segment account for virtually all assimilatory changes and most of the regular ones.[citation needed] Assimilations to an adjacent segment are vastly 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".[1] Many[2] find those terms confusing, as they seem to mean 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, perseveratory, 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
[edit]Anticipatory assimilation to an adjacent segment
[edit]Anticipatory assimilation to an adjacent segment[3] 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 [hæŋkɚtʃif], handbag in rapid speech is pronounced [hæmbæɡ]).
In Italian, voiceless stops assimilated historically to a following /t/:
- Latin octo "eight" > It. otto
- Latin lectus "bed" > letto
- Latin subtus – pronounced suptus "under" > sotto
Italian otto, letto and sotto are examples of historical restructuring: otto and letto no longer contain {{IPA|/kt/ pronounced {{IPA|[tt], and sotto is no longer the structure /bt/ subject to the partial assimilation of devoicing of /b/ and full assimilation to produce [tt]. Over time, phonetic [tt] as a frequent assimilation of /kt/ and /bt/ was rather reinterpreted as reflecting /tt/. The structural sequence /kt/ is now all but absent in Italian since all items in popular speech have undergone the same restructuring: /kt/ > /tt/. On the rare occasion that Italian /kt/ is encountered, however, the same assimilation that triggered the restructuring can occur at the phonetic level. For example, the medical term ictus 'stroke', a relatively recent direct borrowing from Latin, is usually pronounced [ˈiktus] in deliberate speech, but [ˈittus] is frequent in more casual registers.
- Latin ictus > Italian ictus, pronounced either [ˈiktus] or [ˈittus]
Affrication in English
[edit]There has been a notable change recognized across a variety of English dialects regarding the pronunciation of the /tr/ and /dr/ consonant clusters. Starting around the mid-20th century,[4] the alveolar stop in /tr, dr/ has slowly been replaced by a post-alveolar affricate instead, resulting in the all-postalveolar consonant clusters [tʃɹ] and [dʒɹ].[5] This phenomenon also occurs in /str/, resulting in the all-postalveolar consonant cluster [ʃtʃɹ]. The affrication of /tr, dr/ has been seen in American English, British English, Australian English, and New Zealand English.[5] It is suspected that this change has occurred due to assimilation.[5]
One of the first papers that discussed the affrication of /tr, dr/ is "Pre-School Children's Knowledge of English Phonology" by Charles Read, published in 1971.[6] The study discussed in the paper focuses on how children in pre-school analyze the phonetic aspect of language to determine the proper spelling of English words. Read noticed that many of the children involved in the study misspelled words that began with /tr, dr/, spelling words like troubles and dragon as "chribls" and "jragin" respectively.[6] In a different test, Read also found that many of the children believed that words like train and chicken started with /tʃ/.[6]
Anticipatory assimilation at a distance
[edit]Anticipatory assimilation at a distance is rare and usually merely an accident in the history of a specific word.
- Standard Slovene Jevnica (a toponym) > Slovene dialect Vevnica[7][8]
- Slovene Rakitovec > Ratitovec (a mountain ridge)[8]
However, the diverse and common assimilations known as umlaut, in which the phonetics of a vowel are influenced by the phonetics of a vowel in a following syllable, are common and in the nature of sound laws. Such changes abound in the histories of Germanic languages, Romance, Insular Celtic, Albanian, and many other languages.
For example, in the history of English, a back vowel became front if a high front vowel or semivowel (*i, ī, j) was in the following syllable, and a front vowel became higher unless it was already high:
- Proto-Germanic *mūsiz "mice" > Old English mýs /myːs/ > Modern English mice
- PGmc *batizōn "better" > OE bettre
- PGmc *fōtiz "feet" > OE fét > ME feet
On the other hand, Proto-Germanic *i and *u became e, o respectively before *a in the following syllable (Germanic a-mutation) although that had happened significantly earlier:
Another example of a regular change is the sibilant assimilation of Sanskrit in which if there were two different sibilants as the onset of successive syllables, a plain /s/ was always replaced by the palatal /ɕ/:
- Proto-Indo-European *smeḱru- "beard" > Skt. śmaśru-
- PIE *ḱoso- "gray" > Skt. śaśa- "rabbit"
- PIE *sweḱru- "husband's mother' > Skt. śvaśrū-
Lag assimilation to an adjacent segment
[edit]Lag assimilation to an adjacent segment[3] is tolerably common and often has the nature of a sound law.
Proto-Indo-European *-ln- becomes *-ll- in both Germanic and Italic: *ḱl̥nis "hill" > PreLat. *kolnis > Lat. collis; > PGmc *hulliz > OE hyll /hyll/ > hill. The enclitic form of English is elides the vowel and becomes voiceless adjacent to a word-final voiceless nonsibilant: it is [ɪtɪz], that is [ðætɪz] > it's [ɪts], that's [ðæts].
In Polish, /v/ regularly becomes /f/ after a voiceless obstruent:
- kwiat 'flower', pronounced [kfjat], instead of [kvjat]
- twarz 'face', pronounced [tfaʂ], instead of [tvaʂ]
That does not apply across word boundaries and so the placename Grodzisk Wielkopolski is pronounced [ˈɡrɔdʑizɡ vjɛlkɔˈpɔlskʲi], not [ˈɡrɔdʑisk fjɛlkɔˈpɔlskʲi]. In that context, /v/ patterns with other voiced obstruents.
Because of a similar process, Proto-Indo-Iranian *ćw became sp in Avestan: Old Avestan aspa 'horse' corresponds to Sanskrit aśva
Lag assimilation at a distance
[edit]Lag assimilation at a distance is rare and usually sporadic (except when part of a broader change, as for the Sanskrit śaśa- example, above): Greek leirion > Lat. līlium "lily".
In vowel harmony, a vowel's phonetic features are often influenced by those of a preceding vowel. For example, most Finnish case markers come in two forms, with /ɑ/ (written a) and /æ/ (written ä), depending on whether the preceding vowel is back or front. However, it is difficult to know where and how in the history of Finnish an actual assimilatory change took place. The distribution of pairs of endings in Finnish is not the operation of an assimilatory innovation, but it is probably the outbirth of such an innovation long ago.
In the opposite direction, in umlaut, a vowel is modified to conform more closely to the vowel in the next syllable.
Coalescence (fusion)
[edit]Coalescence is a phonological situation whereby adjacent sounds are replaced by a single sound that shares the features of the two originally adjacent sounds. In other words, coalescence is a type of assimilation whereby two sounds fuse to become one, and the fused sound shares similar characteristics with the two fused sounds. Some examples in English include 'don’t you' -> /dəʊnt ju/ -> [dəʊntʃu]. In that instance, /t/ and /j/ have fused to [tʃ]. /tʃ/ is a palato-alveolar sound; its palatal feature is derived from /j/ while its alveolar is from /t/. Another English example is ‘would you’ -> /wʊd ju/ -> [wʊdʒu]. There are examples in other languages, such as Chumburung where /ɪ̀wú ɪ̀sá/ -> /ɪ̀wúɪ̀sá/ becomes [ɪ̀wɪ́sá] - ‘three horns’. In this case, /ɪ/ is retained in the coalescence and the rising tone on /u/ appears on the coalesced sound.[9]
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, /i - lˈalaini/ becomes /e - lˈoleni/ (side). The /a-i/ segment in the first form reduces to /e/. On the other hand, non-reductive coalescence have no reduction in sound segments even though there is evidence of fusion. For example, in Shona, [v_á] [tengesa] (they sell) becomes [ku] [téngésá] (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 /á/ to the vowels.
See also
[edit]Notes
[edit]- ^ Assimilation to a following sound is called regressive or anticipatory assimilation.
- ^ Assimilation to a preceding sound is called progressive assimilation.
- ^ This is called assimilation at a distance.
- ^ This is the case even in slow, highly-articulated speech; excepting some unlearned speakers, as well as Philippine English and similar dialects that pronounce it ~/ˈkʌpbɔːrd/.
References
[edit]Citations
[edit]- ^ Meyer, Paul Georg (2005). Synchronic English Linguistics: An Introduction. Tübingen: Gunter Narr. p. 130.
- ^ For examples, see: Slis, Iman Hans. 1985. The voiced-voiceless distinction and assimilation of voice in Dutch. Helmond: Wibro. 2-3.
- ^ a b Sihler, Andrew L. 2000. Language History: An Introduction. Amsterdam: John Benjamins, pp. 21–22.
- ^ Magloughlin, Lyra (2018-05-07). /tɹ/ and /dɹ/ in North American English: Phonologization of a Coarticulatory Effect (Thesis thesis). Université d'Ottawa / University of Ottawa. doi:10.20381/ruor-21856.
- ^ a b c Smith, Bridget J.; Mielke, Jeff; Magloughlin, Lyra; Wilbanks, Eric (2019-06-19). "Sound change and coarticulatory variability involving English /ɹ/". Glossa: A Journal of General Linguistics. 4 (1). doi:10.5334/gjgl.650. ISSN 2397-1835. S2CID 197750120.
- ^ a b c Read, Charles (1971-04-01). "Pre-School Children's Knowledge of English Phonology". Harvard Educational Review. 41 (1): 1–34. doi:10.17763/haer.41.1.91367v0h80051573. ISSN 0017-8055.
- ^ Savnik, Roman, ed. 1971. Krajevni leksikon Slovenije, vol. 2. Ljubljana: Državna založba Slovenije, p. 266.
- ^ a b Snoj, Marko (2009). Etimološki slovar slovenskih zemljepisnih imen. Ljubljana: Modrijan. pp. 179, 347–348.
- ^ Sibanda, G. (2009). Vowel Processes in Nguni: Resolving the Problem of Unacceptable VV Sequences. Selected Proceedings of the 38th Annual Conference on African Linguistics, 38–55.
Sources
[edit]- Crowley, Terry. (1997) An Introduction to Historical Linguistics. 3rd edition. Oxford University Press.
Assimilation (phonology)
View on GrokipediaFundamentals
Definition
In phonology, assimilation refers to a common sound change process in which one speech sound becomes more similar to, or identical with, an adjacent or nearby sound by adopting one or more of its phonetic features, such as place of articulation, manner of articulation, or voicing.[5] This phenomenon simplifies the articulation of sequences of sounds, often making pronunciation more efficient without altering the underlying lexical meaning.[6] Assimilation can involve partial changes, where only certain features are shared, or total changes, where the target sound fully matches the influencing sound.[5] A key distinction exists between phonetic assimilation and phonological assimilation. Phonetic assimilation is a gradient, automatic process driven by coarticulation, where articulatory gestures overlap continuously, leading to subtle, non-categorical shifts in sound realization that vary by speaking rate or context.[7] In contrast, phonological assimilation is categorical and rule-governed, resulting in discrete changes that alter the phonemic representation of sounds according to the language's phonological system, often applying consistently across morphemes or words.[8] This phonological type reflects abstract patterns encoded in the grammar, distinguishing it from mere physiological overlap.[7] Assimilation operates within a broad scope in natural language, occurring both within the boundaries of individual words (as in morphological or lexical forms) and across word boundaries in phrases or connected speech.[9] Central to this process are the roles of the trigger—the sound that influences the change by spreading its features—and the target—the sound that undergoes modification to align more closely with the trigger.[10] Frequently assimilated features include nasalization, where a sound acquires nasality from a nearby nasal consonant, and velarization, involving the spread of a velar articulatory gesture.[5]Basic Principles
Assimilation in phonology is primarily motivated by the need to reduce articulatory effort in speech production while maintaining perceptual clarity for listeners. Speakers naturally simplify gestures, such as overlapping articulations for adjacent sounds, to achieve ease of production, a process that can lead to one sound adopting features of a neighboring one. This articulatory simplification is often tolerated or even facilitated by the perceptual system, which recovers intended contrasts through contextual cues, ensuring that the overall message remains intelligible.[4][11] The core mechanisms underlying assimilation involve feature spreading, where a phonological feature from a trigger sound propagates to a target sound within the same representation, and perceptual assimilation, which is driven by listener interpretation. In phonological theory, feature spreading occurs autosegmentally, allowing a single feature (e.g., place or manner) to link across segments, thereby unifying their articulation without altering the underlying lexical forms. Perceptually, listeners may infer assimilation as a normalization process, attributing changes to coarticulation rather than distinct phonemes, which reinforces the pattern in language use.[12][4] Assimilation interacts closely with prosodic structure, occurring preferentially within defined domains such as the phonological word or phrase, where stress, intonation, and syllable boundaries influence its application. For instance, assimilation is more prevalent in unstressed syllables or across weak prosodic junctions, as these positions allow greater gestural overlap without disrupting rhythmic or intonational patterns essential for conveying emphasis and phrasing. Syllable structure further constrains assimilation by favoring changes that preserve well-formedness, such as avoiding complex onsets in favor of smoother transitions. While assimilation exhibits universal tendencies as a phonetic predisposition in human speech, its phonological realization varies across language families; for example, Indo-European languages frequently display regressive patterns in connected speech, reflecting historical and typological preferences for anticipatory adjustments. This cross-linguistic commonality underscores assimilation's role in efficient communication, though the extent and conditions differ, with some families showing more extensive vowel harmony or consonant adaptations.[4][13]Classification
By Directionality
In phonological assimilation, directionality refers to the orientation of influence between the target sound, which undergoes change, and the trigger sound, which induces the similarity, either backward (regressive) or forward (progressive) along the linear sequence of sounds.[14][15] Regressive assimilation, also termed anticipatory assimilation, occurs when the target precedes the trigger and modifies in anticipation of it, resulting in a right-to-left spread of features. This process can be schematically depicted as [target] ← [trigger], highlighting the backward direction of influence.[14][15] Progressive assimilation, known as perseveratory or lag assimilation, takes place when the target follows the trigger, with the trigger's features carrying over forward to affect the subsequent sound. It is represented schematically as [trigger] → [target], illustrating the left-to-right propagation.[14][15] The prevalence of regressive versus progressive assimilation is shaped by language-specific factors, including articulatory ease, perceptual salience, and constraint rankings in phonological theory. Regressive assimilation predominates cross-linguistically, as seen in English where coda positions are more prone to change than onsets due to positional faithfulness.[16][17] Progressive assimilation is rarer but attested in select languages, such as certain African ones like Musey, often driven by morphological structure favoring root-to-affix spread.[16]By Proximity
Assimilation in phonology can be classified by proximity, referring to the spatial or structural distance between the target sound, which undergoes change, and the trigger sound, which influences it. This classification distinguishes between local interactions where sounds are immediately adjacent and more extended interactions spanning intervening material. Such categorization highlights how the scope of feature spreading is constrained by phonological structure, independent of whether the assimilation is regressive or progressive.[18][19] Adjacent assimilation occurs when the target and trigger are neighboring segments in the linear string, typically within the same morpheme or across adjacent morpheme boundaries. This type of assimilation facilitates articulatory ease by aligning phonetic properties of closely positioned sounds, such as place or manner of articulation. It is a prevalent process in consonant clusters, where the immediate proximity allows for rapid coarticulation effects.[18][20] In contrast, distant or long-distance assimilation involves non-adjacent segments, with one or more intervening sounds, often crossing syllable or word boundaries. This form commonly manifests as harmony systems, where a feature propagates across a phonological domain, such as in vowel harmony affecting multiple syllables. Long-distance effects challenge traditional locality assumptions in phonology, requiring mechanisms like feature spreading over tiers or correspondence relations to account for the interaction.[21] Structural proximity plays a crucial role in delimiting assimilation, as phonological domains like morpheme boundaries, syllable edges, and prosodic constituents often block or permit feature spreading. Morpheme boundaries frequently constrain assimilation, preventing it from applying across certain junctures while allowing it within roots or affixes. Syllable edges can similarly influence proximity, with assimilation more readily occurring within the same syllable than across boundaries, thereby respecting higher-level prosodic structure.[22][20] Cross-linguistically, adjacent assimilation is more frequent among consonants, appearing in diverse languages for properties like voicing or nasality in clusters. Long-distance assimilation, however, predominates in vowel systems, as seen in harmony patterns that are typologically more common than consonantal counterparts. Typological surveys indicate that while consonant harmony occurs in over 130 languages, it is rarer and more restricted than vowel harmony, underscoring a bias toward local effects in consonantal phonology and extended domains in vocalic.[21][23]By Extent
Assimilation in phonology can be classified by extent according to the degree to which the target sound adopts the features of the trigger sound, ranging from partial changes to complete identity or even fusion into a new segment.[19] Partial assimilation occurs when the target sound adopts only some of the trigger's features, such as place of articulation but not manner, resulting in increased similarity without full identity. For instance, in English, the nasal /n/ may partially assimilate to a following bilabial stop by adopting its place feature while retaining its nasal manner.[2] This type of assimilation is often analyzed using feature geometry, where features are organized hierarchically under nodes like place or manner, allowing selective spreading of subordinate features without affecting higher-level ones.[24] Major class features, such as those under the root node (e.g., consonantal or sonorant), tend to resist partial spreading more than manner features like continuancy, influencing the scope of the change.[25] In contrast, total assimilation involves the target sound becoming identical to the trigger, with all relevant features transferred, leading to a complete merger of the two segments. This is exemplified in cases where a nasal fully copies a following stop's place and manner, as in some varieties of English where /n/ before /m/ becomes /m/.[19] Feature geometry accounts for this by positing spreading of an entire class node or the root node itself, ensuring comprehensive feature adoption.[24] Coalescence represents an extreme form of assimilation by extent, where the target and trigger fuse into a single sound that is distinct from both originals, often combining elements from each rather than merely replicating one.[19] This process goes beyond similarity to create a new phonological entity, frequently involving reciprocal influence under the feature geometry framework.[24] Across languages, the extent of assimilation varies with speech style: total assimilation is more prevalent in rapid or casual speech, where articulatory efficiency favors complete mergers, while partial assimilation predominates in careful or slow speech to maintain clarity.[2] This gradient reflects phonetic motivations, with feature geometry providing a structured way to model how extent correlates with prosodic and contextual factors.[25]Processes and Examples
Regressive Adjacent Assimilation
Regressive adjacent assimilation involves a phonological process where a sound is influenced by and becomes more similar to an immediately following sound, resulting in a backward spread of features such as place or manner of articulation within contiguous positions. This anticipatory change facilitates smoother speech production by aligning articulatory gestures, and it commonly manifests as nasal place assimilation or manner adjustments like affrication.[26] A well-documented case of regressive adjacent place assimilation appears in Latin, where the prefix /ɪn-/ ("in-") changes to /ɪm-/ before labial consonants, as in "impossible" (/ɪmˈpɒsɪbɪl/ in English borrowing), with the alveolar nasal /n/ shifting to the bilabial nasal /m/ to match the labial place of articulation of the following /p/. This morphological assimilation, preserved in many Romance and English derivatives, exemplifies how regressive changes adapt prefixes to stem-initial sounds for phonetic compatibility.[27] Such processes can be represented with a basic phonological rule like C → [+place] / _ [+place] C, where a consonant (C) acquires the place feature of an immediately following consonant bearing that feature, capturing the core mechanism of adjacent regressive place assimilation without reference to underlying representations. Regressive adjacent assimilation is prevalent in Indo-European languages, frequently simplifying consonant clusters through anticipatory feature spread in both historical and synchronic contexts.[28]Regressive Distant Assimilation
Regressive distant assimilation refers to a phonological process where a feature from a sound influences a non-adjacent preceding sound, spreading backwards across intervening segments, as commonly observed in vowel and nasal harmony systems. This type of assimilation operates in the regressive direction, anticipating a following trigger, but extends beyond immediate neighbors, often within bounded domains like the word or morpheme.[29] A prominent example is Turkish vowel harmony, where suffixes regressively agree in vowel features such as backness and rounding with the root vowel, even across multiple intervening vowels. For instance, the root /ev/ 'house' (with front unrounded vowel) takes the suffix -ler for plural, yielding /ev-ler/ 'houses', while the back-voweled root /kol/ 'arm' becomes /kol-lar/.[30] This harmony is typically bounded to the word domain, applying within roots and suffixes but not across word boundaries.[31] Nasal harmony provides another case of regressive distant assimilation, as seen in Yaka (a Bantu language), where a nasal feature from a suffix spreads leftward across non-nasal segments to affect preceding stops or laterals, turning them nasal. For example, the applicative suffix -id- becomes nasalized and triggers nasalization in prior segments, such as in /bee-d-íd-á/ 'cook for', realized with long-distance nasal spread as [bɛ̃ɛ̃-nɛ̃d-ínɛ̃d-á].[32] Such processes are often unbounded within the verb complex but constrained by morphological boundaries.[29] Compared to adjacent assimilation, regressive distant assimilation is rarer and predominantly involves suprasegmental features like vowel height, backness, or nasality rather than local consonant place changes, reflecting articulatory and perceptual efficiencies over longer distances.Progressive Adjacent Assimilation
Progressive adjacent assimilation, also known as perseverative or lagging assimilation, refers to a phonological process in which a sound influences the articulatory or phonetic properties of the immediately following adjacent sound, causing it to become more similar in features such as voicing or manner of articulation.[14] This forward-spreading effect typically occurs within obstruent clusters or across morpheme boundaries, where the trigger segment's feature perseveres onto the target, facilitating smoother transitions in speech production.[33] Unlike regressive assimilation, which anticipates upcoming sounds, progressive assimilation reflects the persistence of prior articulatory gestures.[34] A prominent example appears in English inflectional morphology, particularly with the plural suffix, where the voicing of the stem-final obstruent determines the realization of the suffix as either /s/ or /z/. For instance, the word "dogs" is pronounced [dɒɡz], with the voiced stem-final /ɡ/ causing the underlying voiceless /s/ to become voiced , while "cats" is [kæts], retaining voiceless after the voiceless /t/.[35] This process exemplifies progressive voicing assimilation in adjacent positions, commonly observed in obstruent clusters formed by stem and suffix.[14] Another illustration occurs in Dutch, where progressive voice assimilation affects the initial /d/ of certain function words following a voiceless obstruent. In phrases like "ik pak de bus" ('I take the bus'), the sequence /pɑk də/ surfaces as [pɑktə], with the voiceless /k/ causing the following /d/ to devoice to .[36] Similarly, "wat dan" ('what then') is realized as [vɑt tɑn], devoicing the /d/ after /t/. This adjacent devoicing is restricted to a small class of /d/-initial clitics and highlights manner and voicing changes in progressive direction.[36] Such processes can be formally represented using feature geometry or simple rewrite rules. For the English plural, the rule spreads voicing progressively: the suffix adopts the [±voice] feature of the preceding obstruent, notated as: where is either + or -.[35] In Dutch progressive devoicing, it is: These notations capture the targeted feature change in immediate adjacency.[36] Progressive adjacent assimilation is particularly prevalent in obstruent clusters across languages, as it aids coarticulation by aligning laryngeal settings or stricture degrees between consecutive stops or fricatives, reducing articulatory effort without distant effects.[33] This type aligns with the broader classification of progressive directionality, where influence flows from left to right in linear sequences.[14]Progressive Distant Assimilation
Progressive distant assimilation refers to a phonological process in which a feature from a trigger segment influences a non-adjacent target segment in the progressive (left-to-right) direction, skipping over intervening segments that remain unaffected.[37] This type of assimilation often involves the spreading of features such as nasality or tone across structural boundaries, typically within morphological domains like roots and affixes.[38] Unlike adjacent progressive assimilation, distant variants permit transparent intervening elements, allowing the feature to propagate further.[37] A prominent example occurs in nasal harmony systems of Bantu languages, where nasality spreads progressively from a nasal consonant in the verb root to non-nasal obstruents in suffixes, crossing vowels and other segments. In Kikongo, for instance, a root containing a nasal, such as /tu-nuŋg-idi/ 'we have hidden', results in nasalization of the suffixal /d/ to , yielding [tu-nuŋg-ini], while intervening vowels block nothing and remain oral.[39] This process is morphologically conditioned, applying root-to-suffix but not suffix-to-root, and is analyzed as feature spreading of [nasal] in autosegmental phonology.[38] Similar progressive nasal spreading is observed in other Bantu languages like Coeur d'Alene, where nasality extends rightward across the word.[37] Tone spreading provides another illustration of progressive distant assimilation, particularly in Bantu and Niger-Congo languages, where a high tone (H) from an earlier syllable delinks and associates rightward to non-high tone-bearing units, often across multiple intervening low-tone (L) syllables. In Kikerewe, the underlying form /ku-boh-a/ 'to tie' surfaces as [ku-boh-él-a] with H spreading one syllable rightward to the suffix vowel.[40] In Ndebele, H tone spreads even further, as in /ú-kú-lima/ 'to cultivate' becoming [ú-kú-!lím-is-a] with association to the antepenultimate syllable, skipping L tones.[40] This perseverative spreading is typically domain-limited to the prosodic word and reflects phonetic carryover effects amplified phonologically.[40] Such processes frequently operate within morphological contexts, such as verb inflection or derivation, where the trigger feature in a root or prefix propagates to affixes, enforcing harmony across morpheme boundaries.[37] Progressive distant assimilation is less common cross-linguistically than its regressive counterpart, which dominates in sibilant and other consonant harmonies due to anticipatory articulatory gestures.[38] In Bantu nasal systems, however, progressive directionality prevails, highlighting language-specific preferences in feature geometry.[39]Coalescence
Coalescence is a phonological process in which two adjacent sounds merge into a single new sound, going beyond mere feature similarity to create a fused segment that incorporates elements from both originals.[41] This process differs from total assimilation, in which one sound becomes identical to the adjacent one, because coalescence produces a novel outcome such as an affricate or glide rather than exact identity.[41] A representative example occurs in English connected speech through yod coalescence, where sequences like /dɪd juː/ in "did you" fuse to /dɪdʒuː/, with the alveolar stop /d/ and yod /j/ merging into the palato-alveolar affricate /dʒ/.[42] Historically, Old English initial /kn/ clusters underwent coalescent loss, simplifying to /n/ as in "knee" (from /kneː/ to /niː/), where the velar stop /k/ assimilated to and merged with the following nasal, resulting in segment reduction.[43] The rule for such fusion in yod coalescence can be represented as: for instance, /t j/ → /tʃ/ or /d j/ → /dʒ/, yielding affricates from the combined features.[44] As an extreme case within classification by extent, coalescence exemplifies complete merger in adjacent proximity.[41]Cross-Linguistic Examples
In Korean, a well-documented case of regressive adjacent assimilation involves the nasalization of coda obstruents before a following nasal onset, particularly evident in compound words where the boundary spans the two elements. For instance, in the compound /sup + malk-i/ ('bear cub'), the final obstruent /p/ of the first element assimilates regressively to the nasal manner of the initial /m/ of the second, yielding [sumalk-i]. This process, known as obstruent nasal assimilation (ONA), is phonologically conditioned and applies across morpheme boundaries in compounds, enhancing articulatory ease by avoiding obstruent-nasal sequences.[45] In African languages, Igbo exemplifies regressive distant assimilation through its vowel harmony system, which operates over non-adjacent vowels within words, primarily conditioned by the advanced tongue root ([+ATR]) feature. Regressive assimilation prevails in this system, where suffixes and affixes adjust their vowel quality to match the [-ATR] or [+ATR] specification of the root vowel, even across intervening segments; for example, in verb extensions like /gwu -/ (root with [-ATR] /u/) + /-ta/ (suffix), the suffix vowel shifts regressively to a [-ATR] variant such as /gwu-ta/ rather than preserving its default form. This long-distance harmony enforces uniformity in [ATR] across the word, though progressive effects can occur in rapid speech or compounds, with regressive being the dominant pattern.[46] Among Indigenous languages of North America, Navajo demonstrates progressive distant assimilation in its tone system, where high tone spreads rightward from certain prefixes to subsequent syllables in the complex verb morphology. In disjunct prefix strings, a high tone on an initial prefix like the perfective marker can propagate progressively to toneless vowels in following prefixes or the stem, as in forms where the second-person /ni-/ acquires high tone from a preceding high-toned element, resulting in [ní-]. This assimilation operates over distance, skipping intervening material in the prefix chain, and contributes to the language's tonal melody alignment in polypersonal verbs.[47] Typological studies reveal significant variation and universality in assimilation patterns across languages, with non-Indo-European cases like those in Korean, Igbo, and Navajo highlighting how regressive processes predominate in harmony systems. Surveys indicate a directional bias toward regressive assimilation in vowel and consonant harmony, occurring in the majority of attested systems, while progressive assimilation is rarer but prominent in tone and certain morphological contexts. This distribution underscores assimilation's role in facilitating coarticulation globally, with Asian and African languages often favoring adjacent regressive changes and Indigenous American languages showing distant progressive tendencies in suprasegmentals.[38]Theoretical Context
In Generative Phonology
In generative phonology, assimilation processes were initially modeled using linear rewrite rules in the framework established by Chomsky and Halle's The Sound Pattern of English (SPE), where phonetic features are arranged in a matrix and rules sequentially adjust features to derive surface forms from underlying representations.[48] For instance, regressive nasal place assimilation in English, such as /in + kənsənt/ → [iŋkənsənt], is captured by a rule that changes the place feature of the nasal to match the following coronal or velar consonant, ordered among other phonological rules to ensure correct application.[49] This linear approach treats assimilation as feature replacement, but it faces challenges in accounting for non-local or partial spreading effects without ad hoc stipulations.[49] The shift to nonlinear models in the 1980s addressed these limitations by introducing hierarchical representations and multi-tiered structures, evolving from the segment-based matrices of SPE to autosegmental and geometric frameworks.[50] Autosegmental phonology, pioneered by Goldsmith, represents features on separate tiers linked by association lines, allowing assimilation to be modeled as spreading rather than deletion and insertion.[51] In nasal place assimilation, for example, the place feature of a following consonant spreads leftward to the nasal, creating multiple associations without altering the feature's value. A simplified representation in Yoruba or English might appear as follows, where the nasal /n/ assimilates to a velar /g/:Timing tier: σ σ
/ \ / \
Segmental: n g
Place tier: [velar]----
Association: | |
n g
Timing tier: σ σ
/ \ / \
Segmental: n g
Place tier: [velar]----
Association: | |
n g
[Root](/page/Root)
/ \
Laryngeal Place
|
Dorsal
|
[back]
[Root](/page/Root)
/ \
Laryngeal Place
|
Dorsal
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[back]
| Constraint | AGREE(Place) | IDENT(Place) | *PLACE |
|---|---|---|---|
| [ink] (faithful) | *! | ||
| [iŋk] (assimilated) | * | ||
| [ikk] (coalesced) | *! | * |