Noun. The category of gender was lost; and the loss was total, with no remnants in any of the nominal parts of speech. The category of number was preserved; it had grounds.
Due to the reduction of the unstressed vowels all these came to -es -0 -e or -0 -en
So finally we have -es ,-en, which becomes a competing ending, and a group of conservative nouns retain the vowel interchange. Ending -es was invariably added to form the plural
The Verb. All types of...
verbs existing in Old English — strong, weak, preterite-present and irregular were preserved in Middle English. In each type we find changes due to phonetic developments of this period, but the proportional value of the weak ones is greater and continues to grow, and a tendency is already traced — that is, some of the former strong verbs are drifting in the direction of the weak ones.
The drift was not a comprehensive one; there was even a reverse process, some of the former weak ones became strong.
Grammatical changes in the Middle English period