Middle english and early new english phonetics

During several centuries after the Norman conquest the business of writing was in the hands of French scribes. They introduced into English some peculiarities of French graphic habits. Traces of French traditions in writing have stayed on in English to the present day.

First of all .we must note some changes in the alphabet. Several letters typical of OE gradually came out of use, and some new ones were introduced. The alphabet of the 14th century is basically the same that is in use in our days.
The letter з, which was used in OE to denote several distinct consonant phonemes , is gradually replaced by the letters g and y. Thus, OE зód now appears as good, and the OE зear as yer. The ligature æ also comes into disuse in ME.