The OE sound system developed from the PG system. It underwent multiple changes in the pre-written periods of history, especially in Early OE.
In OE a syllable was made prominent by an increase in the force of articulation; in other words, a dynamic or a force stress was employed. In disyllabic and polysyllabic words the accent fell on the root-morpheme or on the first syllable. Word stress was fixed; it remained on the same syllable in different grammatical forms of the word and, as a rule, did not shift in word-building either.
OE Vowels
The OE vowel system shows 7 points of short and long vowels.
ī ĭ y (short and long) ŭū
ēĕ ōŏ
æ (short and l) ăā
The peculiarity of OE vowels: it showed full symmetry.
Length of vowels was phonological, that is to say it could distingyish different words: gōd (=good NE) and gŏd (god NE)
In ME the following changes occurred (14th c)
Short: Long:
i u i: u:
e o e: o:
a e: o:
a:
The number of short vowels decreased, instead of 7 we find 5 (y-i, æ – a) these vowels merged.
The main process that took place in long vowels was narrowing (ē → e: æ (long)→e: ŏ→o: ā→o:) . The origin of a: it developed from short a in open stressed syllables.