The subject of history of English

7.Old English Vowels. Gradation. Phonetic changes(breaking, i-mutation, back mutation)

The system of vowels in Old English included six long and seven short vowels (monophthongs)

a, æ, e, i, o, u, y (!) - ā, ǣ, ē, ī, ō, ū, ȳ

and four short and four long diphthongs:

ea, eo, ei, io - ēa, ēo, īe, īo

The length of the vowel was a phonemic quality. The words having long and short vowels differed in meaning: ʒod (god) -ʒōd (good), west (west) - wēst (waste).

Assimilative changes are the changes that occurred in the language in specific surroundings.

There are two types of assimilation — regressive and progressive assimilation. If a sound influences the preceding sound, the assimilation is regressive, if it influences the following it sound - it is called progressive assimilation.

gradation, or ablaut - grammatical interchange of vowels in different forms of the verb and in word-formation (чергування голосних у корені слова)

1.Breaking (fracture). This is the process of formation of a short diphthong from a simple short vowel when it is followed by a specific consonant cluster.

a + r+cons, 1+cons. => ea

æ + h+ cons. => ea

e + h final => eo

a > ea arm > earm (arm); talde > tealde (told)

e > eo melcan > meolcan (to milk); fehtan > feohtan (fight)