The Verb ends the first person singular, and the three persons plural, of the present tense, and makes imperative and infinitive, in E. The past tense generally ends in DE or EDE; (Mr Guest has forgotten TE;) sometimes in ED.
As for those two principal endings, the genitive singular in ES, which is the Anglo-Saxon termination retained, and the plural in ES, which is the Anglo-Saxon ending obscured--they happen hardly to fall under Mr Guest's particular regard; but it is easily understood that the Anglo-Saxon hlaford, (lord,) gen. sing. hlaford-ES, had, in Chaucer's day, become lord, lord-ES;--and that scur, (shower,) plural scur-AS, of our distant progenitors had bequeathed to his verse--shour, shour-ES.
Legitimate scepticism surely ceases when it thus appears that ignorance alone has hastily understood that this vowel, extant in this or that word, with a quite alien meaning and use, (--_e.g._ for lengthening a foregoing vowel--softening an antecedent consonant,)--or with none, and through the pure casualty of negligence or of error, might at any time be pressed irregularly into metrical service. Assuredly Chaucer never used such blind and wild license of straightening his measure; but an instructed eye sees in the Canterbury Tales--and in all his poetry of which the text is incorrupt--the uniform application of an intricate and thoroughly critical rule, which fills up by scores, by hundreds, or by thousands, the time-wronged verses of "the Great Founder" to true measure and true music.
To sum up in a few words our own views--First, if you take NO account of the mute E, the great majority of Chaucer's verses in the only justifiable text--Tyrwhitt's Canterbury Tales--are in what we commonly call the TEN-syllabled Iambic metre.
Secondly, if you take account of the metrical E, the great majority of them appear, if you choose so to call them, as ELEVEN-syllabled Iambic verses, or as the common heroic measure with a supernumerary terminal syllable.
Thirdly, if you take NO account of the disputed E, a very large number of the verses, but less apparently than the majority, appear as wanting internally one or two syllables.
Fourthly, if you take account of the said troublesome E, almost universally these deficient measures become filled up to the due complement--become decasyllabic or hendecasyllabic, as the case may be.