Lengthening and shortening of vowels
In addition to the main sources of long monophthongs and diphthongs in Early NE, such as the Great Vowel Shift and the vocalisation of the sonorant [r], there were a few other instances of the growth of long vowels from short ones in some phonetic conditions. These lengthenings resemble Early ME quantitative vowel changes before consonant groups; only this time the consonant sequences which brought about the lengthening were different: [ss], [ft] and [nt]; the sequences mainly affected the vowel [a], e.g. ME plant [plant] > NE plant, ME after ['aftər]>NE after, ME mass [mass]>NE mass.
The reverse change – shortening of vowels – occurred in Early NE before single dental and velar consonants [, d. t, k]. The long vowels subjected to this shortening – [e:] and [u:] – were changing, or had already changed under the Great Vowel Shift, e.g. ME breeth with an open [e:] became [bre:] and was shortened to NE breath [bre]; likewise, ME deed [de:d] > [de:d] > [ded], NE dead. The digraph ea was introduced to show the open quality of the long [e:] prior to the changes.
The long [u:], which became short before [k], and sometimes also before [t], was a product of the shift; this is evidenced by the spelling of such words as book, foot, where long ME [o:] was shown with the help of double o; in these words [o:] became [u:] and was shortened to [u].
The changes that affected consonants in NE are not very numerous. They are as follows.
1) Appearance of a new consonant in the system of English phonemes – [¥] and the development of the consonants [®] and [t] from palatal consonants.
The ME [sj], [zj], [tj], [dj] gave in NE the sounds , [¥], [t], [®], e.g.
[sj] >  Asia, ocean
[zj] > [¥] measure, treasure
[tj] > [t] nature, culture, century
[dj] > [®] soldier
Note should be taken that the above-mentioned changes took place in borrowed words and are connected with the phonetic assimilation of lexical borrowings, whereas the sounds [t], [®], , which appeared in ME developed in native words.
In the numerous loan-words of Romance origin adopted in ME and Early NE the stress fell on the ultimate or penultimate syllable, e.g. ME na'cioun, plea'saunce (NE nation, pleasance). In accordance with the phonetic tendencies the stress was moved closer to the beginning of the word. The final syllables which thus became unstressed, or weakly stressed, underwent phonetic alterations: the vowels were reduced and sometimes dropped; the sounds making up the syllable became less distinct. As a result, some sequences of consonants fused into single consonants.
In Early NE the clusters [sj, zj, tj, dj ] – through reciprocal assimilation in unstressed position – regularly changed into [, ¥, t, ®]. Three of these sounds, [, t, ®] merged with the phonemes already existing in the language, while the fourth, [¥], made a new phoneme. Now the four sounds formed a well-balanced system of two correlated pairs: [, ¥], [t, ®].
2) Certain consonants disappeared at the end of the word or before another consonant, the most important change of this kind affecting the consonant [r]: farm, form, horse, etc.
A number of consonants were vocalised and gave rise to diphthongal glides or made the preceding short vowel long. The vocalisation of [p] in Early ME eliminated the back lingual fricative consonants.
With the disappearance of [x’] the system lost one more opposition – through palatalisation, as “hard” to “soft”. (The soft [k’] and [g’] turned into affricates some time earlier).
3) Another important event was the loss of quantitative distinctions in the consonant system.
In OE long consonants were opposed to short at the phonological level. This is confirmed by their occurrence in identical conditions, their phonological application and the consistent writing of double letters, especially in intervocal position. In Late ME long consonants were shortened and the phonemic opposition through quantity was lost.
The loss of long consonant phonemes has been attributed to a variety of reasons. Long consonants disappeared firstly because their functional load was very low (the opposition was neutralised everywhere except intervocally), and secondly, because length was becoming a prosodic feature, i.e. a property of the syllable rather than of the sound. In ME the length of fhe syllable was regulated by the lengthening and shortening of the vowels; therefore the quantitative differences of the consonants became irrelevant.
4) The fricative consonants [s],  and [f] were voiced after unstressed vowels or in words having no sentence stress – the so-called “Verner’s Law in New English”: possess, observe, exhibition; dogs, cats; the, this, that, there, then, though, etc.
In order to understand the nature of the changes which affected the fricative consonants in ME and in Early NE we must recall some facts from their earlier history. In OE the pairs of fricative consonants – [f] and [v],  and [ð], [s] and [z]-were treated as positional variants or allophones; sonority depended on phonetic conditions: in intervocal position they appeared as voiced, otherwise – as voiceless. In ME and in Early NE these allophones became independent phonemes.
Phonologisation of voiced and voiceless fricatives was a slow process which lasted several hundred years. The first pair of consonants to become phonemes were [f] and [v]. In Late ME texts they occurred in identical phonetic environment and could be used for differentiation between words, which means that they had turned into phonemes. Cf., e.g. ME veyne and feine I'veinc, 'feinc] (NE vein, feign). The two other pairs, [, ð] and [s, z], so far functioned as allophones.
A new, decisive alteration took place in the 16th c. The fricatives were once again subjected to voicing under certain phonetic conditions. Henceforth they were pronounced as voiced if they were preceded by an unstressed vowel and followed by a stressed one, e.g. Early NE possess [po'zes] – the first voiceless [s], which stood between an unstressed and a stressed vowel, had become voiced, while the second [s], which was preceded by an accented vowel, remained voiceless (ME possessen [po'sescn]>NE possess). In the same way ME fishes, doores: takes [‘fics, 'do:rcs, 'ta:kcs] acquired a voiced [z] in the ending. The last three examples show that one phonetic condition – an unaccented preceding vowel – was sufficient to transform a voiceless sibilant into a voiced one; the second condition – a succeeding stressed vowel – was less important: [s] is the last sound of the word. Probably the effect of stress extended beyond the boundaries of the word: the endings took no accent but could be followed by other words beginning with an accented syllable. This supposition is confirmed by the voicing of consonants in many form-words: articles, pronouns, auxiliaries, prepositions; they receive no stress in speech but may be surrounded by notional words which are logically accented
The changes that affected the vowel and the consonant system in New English were great and numerous.
Changes of vowels:
1. Disappearance of vowels in the unstressed position at the end of the word.
2. Changes of all long vowels – the Great Vowel Shift.
3. Changes of two short vowels: [a] > [æ] or ] and [u] > .
4. Changes of two diphthongs: [ai] > [ei], [au] > :].
5. Lengthening of vowels before [r] – due to the vocalization of consonants.
Changes of consonants:
6. Appearance of the consonant [¥] and the consonants [t], [®] in new positions.
7. Disappearance or vocalisation of the consonant [r].
8. Voicing of fricative consonants – Verner’s Law in New English.