1. Middle English period great change Middle English Verbal System

Verbals(Non-finite forms of the verb) in Middle English

Non-finite forms of the verb which in Old English comprised the infinitive and the two participles, have changed in the direction from the nominal to verbal parts of speech. They are no longer declined, nor are they agreed with the nouns; gradually new verbal categories penetrate into their system, and nowadays we speak about the analytical forms of the non-finite forms (passive infinitive, perfect infinitive etc.)
A new non-finite form of the verb arises - the gerund.
The infinitive loses the category of case and acquires a pre-infinitival particle to. It may still be used with what remained of the infinitival suffix (-an, -ian  -en, -n) - to goon, to writen, to spenden, to maken - but the tendency to lose the final consonant is strong.This particle is not used when the infinitive stands after other verbs

Well coude he singe and pleven on a rote...(he could sing and play the rote well)

Participle I, having an active meaning and expressing a process of doing something, in Middle English changes its shape. Its suffix -ende turns into -inde and finally -ynge/-inge due to the processes of weakening of the final sounds and through intermixture with other dialectal forms.
The silver dropes hanginge on the leves (the silver drops hanging on the leaves)
A rose gerland, fressh and wel smellvnge (a rose garland (wreath) fresh and well-smelling)
Originally, the verbal noun was derived from transitive verbs, took an object in the genitive case (which in our times is replaced by of-phrase). But when phonetically it coincided with the participle, it began to behave more freely, now and again taking the direct object. So from the verbal noun without an article but with a direct object we have a grammatical innovation - the Gerund.
Participles II in Middle English - those of strong verbs and those of the weak ones continue to be used with the prefix y- (reduced ʒe-); but this is not universal, and they are sure to lose it in Early Modern English. Yet in Chaucer’s works we may find an interesting phenomenon when depending on the use or non-use of the prefix with the participles of the strong verbs final -n disappears; hoplen but y-holpe, while the Participle II form of the weak verbs does not change, prefixed or non-prefixed broyded - y-broyded.