Since OE lasted for a long period of time some changes occurred in phonetic structure of thr language. The first change is the so called Breaking(Fracture) – переломлення – a specific OE change (it didn’t occur in other Germanic languages). Breaking affected front vowels: æ, e i (long and short). If they were followed by the consonants r, l, n + another consonant or single [h]these vowels turned into diphthongs. They were as if broken into 2 parts.
æ > eaGoth. arms – OE earm
Goth. kalds – OE ceald
e > eoGerm. werk – OE weork
i > ie (later eo) OHG lirnen – OE liornan
The diphthongisationof front vowels due to the influence of palatal consonants.
æ > eaON gaf – OE ™eaf (give)
e > ie ON geban – OE ™iefan
OS kerrian – OE cierran (turn)
æ > eaGoth. jēr - OE ™ear
ē > ie™ēt >™iet (yet)
Mutation (orUmlaut) –перегласовка (borrowing from the German language). Mutation is a kind of assimilation by which the quality of the vowel approximates to the quality of the vowel in the following syllable. It is a regressive assimilation.