Middle English weak verbs.

The evolution of the weak verbs in ME and in Early NE reveals a strong tendency towards greater regularity and order. ME verbs of Class I took the ending -de in the past without an inter¬mediate vowel before the dental suffix — and the ending -ed in the past Participle. They had descended from OE verbs of Class I with a long root syllable. The verbs of Class II, which were marked by -ode, -od in OE, had weakened these endings to -ede, -ed in ME. Since a few verbs of OE Class 1 had -ede, -ed , they are included in ME Class II. Consequently, the only difference between the two classes of weak verbs in ME was the presence or absence of the element -e- be¬fore the dental suffix in the Past tense stem. In Late ME the vowel [e] in unstressed medial and final syllables became very unstable and was lost. This change eliminated the differ¬ences between the two classes and also the distinctions between the 2nd and 3rd principal forms, thus reducing the number of stems in the weak verbs from three to two, Late ME weak verbs are the immediate source of modern standard verbs. The marker of the Past tense and Participle II employed by the weak verbs — the dental suffix -d/-t — proved to be very productive in all historical periods. This simple and regular way of form-building, employed by the majority of OE verbs, attracted hundreds of new verbs in ME and NE. Many former strong verbs began to build weak forms alongside strong ones, the strong forms ultimately falling into disuse. The productivity of this device is borne out by the fact that practically all the borrowed verbs and all the newly-formed verbs in ME and NE built their Past tense and Participle II on the mod¬el of weak verbs.