Phonological history of English

Abbreviations

• C = any consonant
• V = any vowel
• # = end of word
• * = reconstructed
• ** = non-existent
• > = changes into
• >! = changes into, unexpectedly< = is derived from
• PreOE = Pre-Old English
• OE = Old English
• EME = Early Middle English
• LME = Late Middle English
• ME = Middle English
• EModE = Early Modern English
• ModE = Modern English
• GA = General American
• RP = Received Pronunciation
• PrePG = Pre-Proto-Germanic
• PG or PGmc = Proto-Germanic
• NWG = Northwest Germanic
• WG = West Germanic
• OHG = Old High German
• MHG = Middle High German
• ModG = Modern German
• PIE = Proto-Indo-European
• Goth = Gothic
• PN = Proto-Norse
• ON = Old Norse
• OEN = Old East Norse
• OWN = Old West Norse
• OS = Old Saxon

Changes by time period from Late Proto-Germanic to Old English

Late Proto-Germanic period

• Unstressed word-final, and were lost. Early barta > late PGmc bart "you carried ".
• Word-final became .
• * Word-final was then lost after unstressed syllables with nasalization of the preceding vowel. Hence dʰogʰom > early PGmc dagam > late PGmc dagą > Old English dæġ "day ". The nasalisation was retained at least into the earliest history of Old English.
• Word-final was lost after an unstressed syllable. This followed the loss of word-final, because it remained before : PrePGmc bʰr̥n̥t > early PGmc burunt > late PGmc burun "they carried".
• was raised to in unstressed syllables.
• * The original vowel remained when followed by, and was later lowered to.
• Early i-mutation: was raised to when an or followed in the next syllable.
• * This occurred before deletion of word-final ; hence upéri > early PGmc uberi > late PGmc ubiri > German über "over". Compare PIE upér > early PGmc uber > late PGmc ubar > German ober "over".
• * But it occurred after the raising of unstressed to : PIE bʰérete > PGmc berid > birid "you carry ".
• * This also affected the diphthong, which became.
• * As a consequence of this change, >. The Elder Futhark of the Proto-Norse language still contained different symbols for the two sounds.
• z-umlaut: is raised to before.
• * Early PGmc mez "me, dative" > late PGmc miz > Old High German mir, Old Saxon mi, Old Norse mér.
• * This change was only sporadic at best because there were barely any words in which it could have occurred at all, since remained only in stressed syllables. The umlauting effect of remained, however, and in Old West Norse it was extended to other vowels as well. Hence OEN glaʀ, hrauʀ, OWN gler, hreyrr.
• Pre-nasal raising: > before nasal + consonant. Pre-PGmc bʰendʰonom > PGmc bendaną > bindaną > OE bindan > ModE bind.
• * This was later extended in Pre-Old English times to vowels before all nasals; hence Old English niman "take" but Old High German neman.
• Loss of before, with nasalization and compensatory lengthening of the preceding vowel.
• * The nasalization was eventually lost, but remained through the Ingvaeonic period.
• * Hence Pre-PGmc tongjonom > PGmc þankijaną > OE þencan > ModE think, but PrePG tonktos > PGmc þanhtaz > þą̄htaz > OE þōht > ModE thought.
• * This change followed the raising of before a nasal: PGmc þenhaną > þinhaną > þį̄haną > Gothic þeihan.
• Final-syllable short vowels were generally deleted in words of three syllables or more. PGmc biridi > Goth baíriþ " carries", and also PGmc -maz, -miz > -mz.

Northwest Germanic period

• Allophonic i-mutation/Germanic umlaut: Short back vowels were fronted when followed in the next syllable by or, by i-mutation: >, >, >
• * In this initial stage, the mutated vowels were still allophonically conditioned, and were not yet distinct as phonemes. Only later, when the and were modified or lost, were the new sounds phonemicized.
• * i-mutation affected all the Germanic languages except for Gothic, although with a great deal of variation. It appears to have occurred earliest, and to be most pronounced, in the Schleswig-Holstein area, and from there to have spread north and south. However, it is possible that this change already occurred in Proto-Germanic proper, in which case the phenomenon would have remained merely allophonic for quite some time. If that is the case, that would be the stage reflected in Gothic, where there is no orthographic evidence of i-mutation at all.
• * Long vowels and diphthongs were affected only later, probably analogically, and not in all areas. Notably, they were not mutated in most Dutch dialects, whereas short vowels were.
• a-mutation: is lowered to when a non-high vowel follows in the next syllable.
• * This is blocked when followed by a nasal followed by a consonant, or by a cluster with in it. Hence PG gulþą > OE/ModE gold, but PG guldijaną > OE gyldan > ModE gild.
• * This produces a new phoneme, due to inconsistent application and later loss of word-final vowels.
• Final-syllable long vowels were shortened.
• * Final becomes, later raised to. PG sagō > OE sagu, ON sǫg.
• * Final becomes in ON, in West Germanic. PG hailidē > ON heilði, but OE hǣlde, OHG heilta.
• * The final long diphthong loses its final element and usually develops the same as from that point on. PG gebōi > NWG gebō > ON gjǫf, OHG gebu, OE giefe.
• "Overlong" vowels were shortened to regular long vowels.
• PG becomes. This preceded final shortening in West Germanic, but postdated it in North Germanic.
• Unstressed diphthongs were monophthongized. >, >. The latter merged with ō from shortened overlong ô. PG sunauz > NWG sunōz > ON sonar, OE suna, OHG suno; PG nemai > NWG nemē > ON nemi, OE nime, OHG neme; PG stainai > NWG stainē > ON steini, OE stāne, OHG steine.

West Germanic period

• Loss of word-final.
• * This change occurred before rhotacization, as original word-final was not lost.
• * But it must have occurred after the Northwest Germanic split, since word-final was not eliminated in Old Norse, instead merging with.
• * was not lost in single-syllable words in southern and central German. Compare PG miz > OS mi, OE me vs. OHG mir.
• * The OE nominative plural -as, OS nominative plural -ōs may be from original accusative plural -ans, due to the Ingvaeonic Nasal-Spirant law, rather than original nominative plural -ōz, which would be expected to become *-a.
• Rhotacization: >.
• * This change also affected Proto-Norse, but only much later. and were still distinct in the Danish and Swedish dialect of Old Norse, as is testified by distinct runes.
• * PG deuzą > Goth dius; OE dēor > ModE deer
• Intervocalic ðw > ww.
• Hardening: ð > d, β > v, and ɸ > f.
• * > medially; in Old English this is extended to word-final position by analogy with inflected forms.
• West Germanic gemination: single consonants followed by except became double. This only affected consonants preceded by a short vowel, because those preceded by a long vowel or by another consonant were never followed by due to Sievers' law.
• * PG bidjaną, *habjaną > OE biddan, habban > ModE bid, ''have''

Ingvaeonic and Anglo-Frisian period

• Ingvaeonic nasal spirant law: Loss of nasals before fricatives, with nasalization and compensatory lengthening of the preceding vowel. Hence PG munþaz became ModG Mund but in Ingvaeonic dialects first became mų̄þa. Old English then denasalised the vowels, giving OE mūþ > ModE "mouth".
• * Following this >. PrePG donts > PG tanþs > tą̄þ > tǭþ > OE tōþ > ModE "tooth". This also applied to arising earlier in Proto-Germanic: PG þanhtǭ > Late PG þą̄htǭ > OE þōhte > ModE " thought".
• Anglo-Frisian brightening:
• * Fronting of to . Hence OE dæġ "day", plural dagas "days".
• * This does not affect nasal. And since this is a back vowel, in a preceding syllable was prevented from being fronted as well. This created an alternation between the infinitive in *-aną and strong past participle in *-ana, where the former became -an in OE but the latter became *-ænæ > -en.
• * Fronting of to .
• Final-syllable, and are lost.
• * No attested West Germanic languages show any reflexes of these vowels. However, the way it affected the fronting of as described above shows that at least was retained into the separate history of Anglo-Frisian.

Old English period

• Breaking of front vowels.
• * Most generally, before, and + consonant, but exact conditioning factors vary from vowel to vowel.
• * Initial result was a falling diphthong ending in, but this was followed by diphthong height harmonization, producing short,, and from short,, and. Long,, and came from long,, and.
• ** Written ea, eo, io, where length is not distinguished graphically.
• * Result in some dialects, for example Anglian, was back vowels rather than diphthongs. West Saxon ceald; but Anglian cald > ModE cold.
• Diphthong height harmonization: The height of one element of each diphthong is adjusted to match that of the other.
• * > through this change, possibly through an intermediate stage. PG stainaz > OE stān > ModE stone.
• * was first fronted to and then harmonized to. PG draumaz > OE drēam "joy". PG dauþuz > OE dēaþ > ModE death. PG augō > OE ēage > ModE eye.
• * is harmonized to.
• A-restoration: Short is backed to when a back vowel follows in the next syllable.
• * This produces alternations such as OE dæġ "day", pl. dagas.
• Palatalization of velar consonants: were palatalized to in certain complex circumstances. A similar palatalization happened in Frisian, but by this point the languages had split up; the Old English palatalization must be ordered after Old-English-specific changes such as a-restoration.
• * Generally, the velar stops were palatalized before or ; after when not before a vowel; and was palatalized at the beginning of a word before front vowels.
• * was palatalized in somewhat broader circumstances: By any following front vowel, as well as by a preceding front vowel when a vowel did not immediately follow the.
• * later becomes, but not before the loss of older below.
• * is palatalized in almost all circumstances. PG skipaz > ModE ship, but West Frisian skip. PG skurtijaz > OE scyrte > ModE shirt, but > ON skyrt > ModE skirt. An example of retained is PG aiskōną > OE ascian > ModE ask; there is evidence that OE ascian was sometimes rendered metathetized to acsian, which is the presumed origin of ModE ask.
• Palatal diphthongization: Initial palatal,, trigger spelling changes of a > ea, e > ie. It is disputed whether this represents an actual sound change or merely a spelling convention indicating the palatal nature of the preceding consonant.
• * Similar changes of o > eo, u > eo are generally recognized to be merely a spelling convention. Hence WG > OE geong > ModE "young"; if geong literally indicated an diphthong, the modern result would be *yeng. It is disputed whether there is Middle English evidence of the reality of this change in Old English.
• i-mutation: All back vowels were fronted before a in the next syllable, and front vowels were raised.
• * > ;
• * > > ;
• * > ;
• *, > > ; this also applied to the equivalent short diphthongs.
• * Short > by an earlier pan-Germanic change under the same circumstances; often conflated with this change.
• * This had dramatic effects in inflectional and derivational morphology, e.g. in noun paradigms ; verb paradigms ; nominal derivatives from adjectives, from verbs, and from other nouns ; verbal derivatives ; comparative adjectives. Many echoes of i-mutation are still present in the modern language.
• Close-vowel loss: Loss of word-final and except when following a short syllable For example, PIE sunus > PG sunuz > OE sunu "son ", PIE peḱu > PG fehu > OE feohu "cattle ", PIE wenis > PG winiz > OE ƿine "friend ", but PrePG pōdes > PG fōtiz > WG fø̄ti > OE fēt "foot ".
• Loss of and following a long syllable.
• * A similar change happened in the other West Germanic languages, although after the earliest records of those languages.
• * This did not affect the new formed from palatalisation of PG, suggesting that it was still a palatal fricative at the time of the change. For example, PG wrōgijanan > early OE * > OE ƿrēġan.
• * Following this, PG occurred only word-initially and after .H-loss: Proto-Germanic is lost between vowels, and between and a vowel. The preceding vowel is lengthened.
• * This leads to alternations such as eoh "horse", pl. ēos, and ƿealh "foreigner", pl. ƿēalas.
• Vowel assimilation: Two vowels in hiatus merge into a long vowel.
• * Some examples come from h-loss. Others come from loss of or between vowels, e.g. PG frijōndz > OE frīond > frēond "friend"; PG saiwimiz "sea " > *sǣƿum > OE sǣm.
• Back mutation: Short e, i and a are sometimes broken to short eo, io, and ea when a back vowel follows in the next syllable.
• * Hence seofon "seven" < PG *sebun, mioluc, meoluc "milk" < PG *meluks.
• Palatal umlaut: Short e, eo, io become i before hs, ht.
• * Hence riht "right", siex "six".
• Vowel reductions in unstressed syllables:
• * became in final syllables, but usually appears as o in medial syllables.
• * and became in final syllables.
• * normally became in a final syllable except when absolutely word-final.
• * In medial syllables, short are deleted; short are deleted following a long syllable but usually remain following a short syllable, merging to in the process; and long vowels are shortened.
• are unrounded to, respectively. This occurred within the literary period.
• * Some Old English dialects retained the rounded vowels, however.
• Early pre-cluster shortening: Vowels were shortened when falling immediately before either three consonances or the combination of two consonants and two additional syllables in the word.
• * Thus, OE gāst > ModE ghost, but OE găstliċ > ModE ghastly and OE crīst > ModE Christ, but OE crĭstesmæsse > ModE Christmas.
• * Probably occurred in the seventh century as evidenced by eighth century Anglo-Saxon missionaries' translation into Old Low German, "Gospel" as Gotspel, lit. "God news" not expected *Guotspel, "Good news" due to gōdspell > gŏdspell.
• and were lowered to and between 800 and 900 AD.
• Initial became in late Old English. This occurred within the literary period, as evidenced by shifting patterns in alliterative verse.

Changes by time period from Middle English to American-British split

The Middle English Period

• Homorganic lengthening: Vowels were lengthened before,,,, probably also,,, when not followed by a third consonant or two consonants and two syllables.
• * This probably occurred around AD 1000.
• * Later on, many of these vowels were shortened again; but evidence from the Ormulum shows that this lengthening was once quite general.
• * Remnants persist in the Modern English pronunciations of words such as child, field, old, climb, find, long and strong, fiend, found.
• Pre-cluster shortening: Vowels were shortened when followed by two or more consonants, except when lengthened as above.
• * This occurred in two stages, the first stage occurring already in late Old English and affecting only vowels followed by three or more consonants, or two or more consonants when two syllables followed.
• Diphthong smoothing: Inherited height-harmonic diphthongs were monophthongized by the loss of the second component, with the length remaining the same.
• * and initially became and.
• * and initially became and.
• Middle English stressed vowel changes:
• * and became and, respectively.
• * and merged into.
• * New front-rounded and were unrounded to and.
• * and were unrounded to and.
• -dər > -ðər. This also occurred after the final reduction.
• became or, depending on surrounding vowels.
• New diphthongs formed from vowels followed by or .
• * Length distinctions were eliminated in these diphthongs, yielding diphthongs plus borrowed from French.
• * Middle English breaking: Diphthongs also formed by the insertion of a glide or preceding.
• Mergers of new diphthongs:
• * Early on, high-mid diphthongs were raised: merged with, merged with and merged with .
• * In Late Middle English, and merge as, so that vain and vein are homophones.
• Trisyllabic laxing: Shortening of stressed vowels when two syllables followed.
• * This results in pronunciation variants in Modern English such as divine vs divinity and south vs. southern.
• Middle English open syllable lengthening: Vowels were usually lengthened in open syllables, except when trisyllabic laxing would apply.
• Reduction and loss of unstressed vowels: Remaining unstressed vowels merged into.
• * Starting around 1400 AD, is lost in final syllables.
• Initial clusters,, were reduced by loss of.
• Voiced fricatives became independent phonemes through borrowing and other sound changes.
• before back vowel becomes ; becomes.
• * Modern English sword, answer, lamb.
• * in swore is due to analogy with swear.
• The cluster, present in words imported from Norman, is deaffricated, and merges with, thus merging sell and cell.
• * But unlike French, and are fully preserved.
• In late Middle English, the extremely rare word-initial cluster fn- became sn-.
• *It has been suggested that the change could be due to a misinterpretation of the uncommon initial sequence fn- as ſn-.

Up to Shakespeare's English

• H-loss completed: lost in most dialects, so that e.g. taught and taut become homophones, likewise bow and bough. However, when preceded by /u/, it sometimes got labialized to /f/, as in enough.
• and when not followed by a vowel undergo mutations:
• * Before, a coronal consonant or word-finally, they are diphthongized to and. After this, the combinations and lose their in most accents, affecting words like talk, caulk, and folk. Words acquired after this change were not affected.
• * Before, the becomes silent, so that half and calf are pronounced with, and salve and halve are pronounced with. is exempt, so that solve keeps its. is not wholly exempt, as the traditional pronunciation of golf was.
• * Before, become, as in alms, balm, calm, palm; Holmes.
• * Some words have irregular pronunciations, e.g. from non-standard dialects or spelling pronunciations.
• Short develop into lax
• Great Vowel Shift; all long vowels raised or diphthongized.
• * become, respectively.
• * become, respectively.
• * become or, later and.
• * New developed from old .
• ** Thus, effectively rotated in-place.
• * Later, the new are shifted again to in Early Modern English, causing merger of former with ; but the two are still distinguished in spelling as ea, ee. the meet-meat merger
• Initial cluster reductions:
• * merges into ; hence rap and wrap become homophones.
• Doubled consonants reduced to single consonants.
• Loss of most remaining diphthongs.
• * became, merging with the vowel in broad and the of the lot–cloth split below.
• * The long mid mergers: are raised to, eventually merging with, so that pane and pain, and toe and tow, become homophones in most accents.
• * The above two mergers did not occur in many regional dialects as late as the 20th century.
• * merge to, so that dew, duke and new now have the same vowel.
• ** This would become in standard varieties of English, and later still in some cases through "Yod-dropping".
• ** remains in Welsh English and some other non-standard varieties.
• * and merge to //, the only Middle English diphthong that remains in the modern standard English varieties.

Up to the American–British split

• At some preceding time after Old English, all become.
• * Much of Scottish English has consistently.
• /p t k/ develop aspirated allophones /pʰ tʰ kʰ/ when they occur alone at the beginning of stressed syllables.
• Initial cluster reductions:
• * both merge into ; hence gnat and Nat become homophones; likewise not and knot.
• The foot–strut split: In southern England, becomes unrounded and eventually lowered unless preceded by a labial and followed by a non-velar. This gives put but cut and buck. This distinction later become phonemicized by an influx of words shortened from to both before and after this split.
• Ng-coalescence: Reduction of in most areas produces new phoneme.
• In some words, coalesce to produce with /ʒ/ being a new phoneme, a sound change known as yod-coalescence, a type of palatalization: nature, mission, procedure, vision.
• * These combinations mostly occurred in borrowings from French and Latin.
• * Pronunciation of -tion was from Old French, thus becoming.
• * This sound mutation still occurs allophonically in Modern English: did you → didjou.
• /ɔ/ as in lot, top, and fox, is lowered towards /ɒ/.
• Long vowels, from ME, inconsistently shortened, especially before : sweat, head, bread, breath, death, leather, weather
• * Shortening of occurred at differing time periods, both before and after the centralizing of to ; hence blood versus good : also foot, soot.
• The Meet–''meat merger: raises to . Thus Meet and meat become homophones in most accents. Words with that were shortened avoided the merger, also some words like steak and great simply remained with an, merging with words like name, so now death, great, and meat have three different vowels.
• Changes affect short vowels in many varieties before an at the end of a word or before a consonant:
• * as in start and as in north are lengthened.
• * merge before, so all varieties of ModE except for some Scottish English and some Irish English have the same vowel in fern, fir and fur.
• * Also affects vowels in derived forms, so that starry no longer rhymes with marry.
• , as in cat and trap, fronted to in many areas. In certain other words it becomes, for example father. is actually a new phoneme deriving from this and words like calm.
• * Most varieties of Northern England English, Welsh English and Scottish English retain in cat, trap etc.
• The lot–cloth split: in some varieties, lengthening of before voiced velars and voiceless fricatives. Hence American English long, dog, loss, cloth, off with .
• becomes in many words spelt oo: for example, book, wool, good, foot''. This is partially resisted in the northern and western variants of English English, where words ending in -ook might still use.

Changes by time period from after American-British split to after World War II

After American–British split, up to World War II

• Split into rhotic and non-rhotic accents: syllable-final is lost in much of the English of England, with exceptions including West Country English and Lancashire dialect.
• * The loss of coda causes significant changes to preceding vowels:
• ** merges with in unstressed syllables, in stressed syllables
• ** become
• ** become long vowels,.
• ** All other short vowels plus coda merge as a new phoneme, the long mid-central vowel.
• ** Long vowels with a coda,, become new centering diphthongs,.
• ** Long vowels before intervocalic are also diphthongised, thus dairy from earlier.
• * The Southern Hemisphere varieties of English are also non-rhotic.
• * Non-rhotic accents of North American English include New York City, Boston, and older Southern.
• Unrounding of : as in lot and bother is unrounded in Norwich, the West Country, in Hiberno-English and most of American English
• * The Boston accent is an exception where the vowel is still rounded.
• * In North American English, in father is typically also unlengthened to merge with the unrounded, resulting in the father–''bother merger: so that most North American dialects only have the vowel.
• ** Out of North American dialects that have unrounded, the only notable exception is New York City.
• The trap–bath split: in Southern England inconsistently becomes before and or followed by another consonant.
• * Hence RP has pass, glass, grass, class with but mass, crass with.
• * All six words rhyme in most American, Scottish English and Northern England English.
• The long vowels from the Great Vowel Shift become diphthongs in many varieties of English, though not in Scottish and Northern England English.
• Voicing of to results in the wine–whine merger in most varieties of English, aside from Scottish, Irish, Southern American, and New England English.
• In American, Canadian, Australian and to some degree New Zealand English, are flapped or voiced to between vowels.
• * Generally, between vowels or the syllabic consonants, when the following syllable is completely unstressed: butter, bottle, bottom.
• * But and before syllabic is pronounced as a glottal stop, so cotton.Happy-tensing : final lax becomes tense in words like happ. Absent from some dialects like Southern American English, Traditional RP, cultivated South African English, most forms of Northern England English and to some degree Scottish English.Line–loin merger: merger between the diphthongs and in some accents of Southern England English, Hiberno-English, Newfoundland English, and Caribbean English.H''-dropping begins in England and Welsh English, but this does not affect the upper-class southern accent that developed into Received Pronunciation, nor does it affect the far north of England or East Anglia.
• Reversal of the lot-cloth split in British English so words like cloth revert to being pronounced with. The split survives in American English.

After World War II

• Restoration of post-vocalic in some non-rhotic accents of Southern American English as well as in New York City English and Eastern New England English.
• Changes to the low front vowel
• * /æ/ raising: raising, lengthening or diphthongization of in some varieties of American English in various contexts, especially before nasal consonants, resulting in. Some linguistics research suggests that raising existed since the American colonial era, due to relic evidence of this feature in some of the Northern and Midland U.S.
• * Bad–lad split: the lengthening of to in some words, found especially in Australian English and to a degree in Southern English English.
• * Raising to in New Zealand English and South African English.
• * Lowering to in Received Pronunciation, Canadian English, Western American English, and Australian English.
• Changes to the non-high back vowels and :
• * is raised to and is raised to in Southern England English, Australian English and New Zealand English.
• * Cot–caught merger: lowering of to in Western American English and some dialects in New England and the Midland region. This sound change is still in progress.
• Fronting of high back vowels /uː/, /oʊ/, /ʌ/ and /ʊ/.
• * In many varieties of English, is fronted to,, or
• ** Resistance occurs in Northern American English and New York City English.
• * In Australian English, New Zealand English, most English of England and some American English, is fronted to,, or
• ** Resistance occurs in most varieties of Northern England English, as well as Scottish English, Northern American English and New York City English.
• * In many varieties is fronted to.
• * In Southern England English, is fronted to.
• Lock–loch merger: the replacement of with among some younger Scottish English speakers from Glasgow. Pin–''pen merger: the raising of to before nasal consonants in Southern American English and southwestern varieties of Hiberno-English.
• Horse-hoarse merger: and merge in many varieties of English
• Vowel mergers before intervocalic in most of North America :
• * Mary–marry–merry merger: and merge to.
• * Hurry-furry merger: and merge to.
• * Mirror-nearer merger and merge or are very similar, the merged vowel can be quite variable.
• T-glottalization becomes increasingly widespread in Great Britain.
• Various treatments of the th sounds, the dental fricatives :
• * Th-fronting: merger with the labiodental fricatives
• * Th-stopping: shift to dental stops, or merger with alveolar stops
• * Th-debuccalization: lenition to
• * Th-alveolarization: merger with alveolar fricatives
• L''-vocalization: changes to an approximant or vowel, such as, or. This occurs in Estuary English and other dialects.Yod-dropping: loss of in some consonant clusters. Though it occurs in some environments in many British English dialects, it is most extensive in American and Canadian English.
• Northern Cities Vowel Shift in Inland Northern American English:
• * raising and tensing of
• * fronting of
• * lowering of
• *backing and lowering of
• * backing of
• * lowering and backing of
• Changes to centering diphthongs in non-rhotic varieties of English :
• * smooth to : near, square, start, force.
• * either
• ** smooths to,
• ** breaks to,
• ** lowers and merges with :
• *Triphthongs smooth to or .
• Other changes to diphthongs in Received Pronunciation:
• * /eɪ/ is lowered to .
• * /aɪ/ is retracted to .
• * /ɔɪ/ is raised to .
• * /aʊ/ is fronted from to .

Examples of sound changes

• Some changes are morphological ones that move a word from a rare declension to a more common one, and hence are not so surprising: e.g. *þrī "three" >! *þriu and keːr "heart" >! kérd-oː.
• Some changes are assimilations that are unexpected but of a cross-linguistically common type, e.g. "four" >! where ** would be expected by normal sound change. Assimilations involving adjacent numbers are especially common, e.g. kʷetwṓr "four" >! petwṓr by assimilation to pénkʷe "five".
• On the other extreme, the Early Modern English change of "one" >! is almost completely mysterious. Note that the related words alone and only did not change.

Summary of vowel developments

Development of Middle English vowels

Monophthongs

1. the short vowels indicated in Old English spelling as, and ;
2. the long equivalents,, and often when directly followed by two or more consonants ;
3. occasionally, the long vowel when directly followed by two consonants, particularly when this vowel corresponded to West Saxon Old English.

1. when not in any of the contexts indicated below, as in man, sack, wax, etc.
2. A vowel pronounced in General American and in Received Pronunciation when preceded by and not followed by the velar consonants, as in swan, wash, wallow, etc.
3. or when followed by a written, as in hard, car, etc.
4. But or when both preceded by and followed by written, as in war, swarm, etc.
5. when followed by an plus either a consonant or the end of a word, as in small, walk, etc.
6. when followed by, as in palm, calm, etc.
7. In RP only, the pronunciation is often found when followed by an unvoiced fricative, i.e., or, as in glass, after, path, etc. This does not apply to GA and also unpredictably does not affect a number of words of the same form, e.g. crass, math, etc.

Diphthongs