Changes in the Designation of Vowels

The letter æ was replaced by a, and the letter ǣ was replaced by the letter e, accompanied by the phonetic change of æ > a, ǣ > e: OE æppel > ME appel, OE lǣtan > ME leten.

The letter y (which had denoted [ü] in OE) came to be used as an equivalent of the letter i; it represented the sounds [ı] and [j], e.g.

OE night > ME nyght, OE his > ME his, hys; OE dæʒ > ME day.

Moreover, there was a tendency to use the letter «i» at the beginning and in the middle of words and the letter «y» at the end of a word to separate it from the next one, as there were often no intervals between words.

The letter o was employed not only for the sound [o] but also for the sound [u] That happened mostly when u stood close to n, m, v or w, i.e. where too many vertical lines made reading of a hand-written text difficult, e.g.

OE cuman > ME comen. This is why ME words like come, some, son have the letter o instead of u.

Many letters changed their signification. The letter u (which had denoted only one sound [u] in OE) was employed after the French fashion to denote also the labial front vowel [ü], formerly expressed by «y», e.g.

OE bysiʒ > ME busy. The corresponding long vowel [ü] was usually marked by ui, e.g.

OE fӯr > ME fuir (fire).

The sound [ū] came to be denoted by the digraphs ou, ow. Moreover, there was a tendency to use «ow» at the end of a word (occasionally in medial position) and «ou» in other positions, e.g. OE tūn > ME town, OE sūþ > ME south, OE nū > ME now.

It became usual to mark the length of a vowel by doubling it, especially in closed syllables.

Thus, long close [ ] came to be denoted by ee; open [ ] was denoted by ea, e.g.

OE fēt > ME feet, OE swēt > ME sweet, OE sǣ > ME sea.

The sound [e] (chiefly in French borrowings) was also denoted by the digraphs «ie» or «ei», e.g. ME chief < OF chef, ME deceiven < OF deceiver.