All the changes described above affected accented vowels. The development of vowels in unstressed syllables, final syllables in particular, was basically different. Whereas in stressed position the number of vowels had grown (as compared with the PG system), due to the appearance of new qualitative differences, the number of vowels distinguished in unstressed position had been reduced. In unaccented syllables, especially final, long vowels were shortened, and thus the opposition of vowels – long to short – was neutralised. Cf. OE nama (NE name) to the earlier *namon. It must also be mentioned that some short vowels in final unaccented syllables were dropped. After long syllables, that is syllables containing a long vowel, or a short vowel followed by more than one consonant, the vowels [i] and [u] were lost. Cf. the following pairs, which illustrate the retention of [u] and [i] after a short syllable, and their loss after a long one: OE scipu and sceap (NE ships, sheep, pl from *skeapu); OE werian—demon (NE wear, deem; cf. Gt domjan).
Old English Vowel System (9th-10th c.)
The vowels shown in parentheses were unstable and soon fused with resembling sounds: [a] with [a] or [o], [ie, ie:] with [y, y:].
The vowels are arranged in two lines in accordance with the chief phonemic opposition: they were contrasted through quantity as long to short and were further distinguished within these sets through qualitative differences as monophthongs and diphthongs, open and close, front and back, labialised and non-labialised. Cf. some minimal pairs showing the phonemic opposition of short and long vowels:
OE dæl — dæl (NE dale, 'part') is — īs (NE is, ice))col — cōl (NE coal, cool).
The following examples confirm the phonemic relevance of some qualitative differences:
The OE vowel system displayed an obvious tendency towards a symmetrical, balanced arrangement since almost every long vowel had a corresponding short counterpart. However, it was not quite symmetrical: the existence of the nasalised [a] in the set of short vowels and the debatable phonemic status of short diphthongs appear to break the balance.
All the vowels listed in the table could occur in stressed position. In unstressed syllables we find only five monophthongs, and even these five vowels could not be used for phonemic contrast:
i – ænig (NE any)
e – stāne, Dat. sg of stān as opposed to
a – stānaGen. pl of the same noun (NE stone)
o – bæron — Past pl Ind (of beran as opposed to bæren. Subj. (NE bear)
u — talu (NE tale), Nom. sg as opposed to tale in other cases
The examples show that [e] was not contrasted to [i], and [o] was not contrasted to [u]. The system of phonemes appearing in unstressed syllables consists of three units: e/i a o/u
Consonant Changes in Pre-Written Periods
On the whole, consonants were historically more stable than vowels, though certain changes took place in all historical periods.
It may seem hat being a typical OG language OE ought to contain all the consonants that arose in PG under Grimm's and Verner's Law. Yet it appears that very few noise consonants in OE correspond to the same sounds in PG; for in the intervening period most consonants underwent diverse changes: qualitative and quantitative, independent and positional.
Some of the consonant changes dated in pre-written periods are referred to as "West Germanic" (WG) as they are shared by all the languages of the WG subgroup; WG changes may have taken place at the transitional stage from PG to Early OE prior to the Germanic settlement of Britain.