TL;DR: As late as the beginning of the 17th century, the editor Thomas Speght claimed that it was possible for a skillful reader to scan Chaucer. But he modernized Chaucer’s spelling, making it hard for anyone after him to do the same!
It seems that in the mid-16th century, some people still knew, or thought they knew, how to scan Chaucer. Gavin Douglas, in the preface to his translation of Virgil’s Aeneid, published 1533, praised Chaucer as “horleige and reguleir” (that is, as regular as a clock), and the antiquarian John Stow, in the preface to his 1561 edition of Chaucer’s works, wrote without further comment that the poet possessed “soche perfection in metre”. But by the end of the 16th century the skill must have fallen into desuetude, for Thomas Speght, the editor of The Workes of Our Ancient and learned English Poet, Geoffrey Chaucer, felt the need to justify the claim that Chaucer could be scanned. In his preface to the second edition (1602) he wrote thus:
And for his verses, although in divers places they may seeme to us to stand of unequall measures: yet a skilfull Reader, that can scan them in their nature, shall find it otherwise. And if a verse here and there fal out a sillable shorter or longer than another, I rather aret it to the negligence and rape of Adam Scrivener,† that I may speake as Chaucer doth, than to any unconning or oversight in the Author: For how fearfull he was to have his works miswritten, or his verse mismeasured, may appeare in the end of his fift booke of Troylus and Creseide, where he writeth thus:
And for there is so great diversitie
In English and in writing of our tongue,
So pray I God that none miswrite thee,
Ne thee mismetre for defaut of tongue, &c.
Moreover, whereas in the explanation of the old words, sundry of their significations by me given, may to some seeme conjectural, yet such as understand the Dialects of our tongue, especially in the North, and have knowledge in some other languages, will judge otherwise […]
Thomas Speght (1602). Preface to The Workes of Our Ancient and learned English Poet, Geoffrey Chaucer. London: Adam Islip.
† Chaucer’s scrivener (copyist), to whom he wrote a short complaint in verse.
This passage implies that Speght knew that the pronunciation of words had changed, and that Chaucer’s verse had scanned in the original. And he indicates that at that period there existed regional dialects which preserved old pronunciations and vocabulary, so that a skilful reader familiar with these dialects could make out Chaucer’s scansion. (Sadly Speght gives us no other clues as to how much he knew about the change in pronunciation—he was more concerned with explaining Chaucer’s “old and obscure words”.)
However, lacking knowledge of Middle English, Speght’s readers must have had difficulty in making out these implications. And sure enough, less than a century later, John Dryden read Speght’s claim that Chaucer could be scanned by a skilful reader and did not believe it:
’Tis true, I cannot go so far as he who publish’d the last Edition of him; for he would make us believe the Fault is in our Ears, and that there were really Ten Syllables in a Verse where we find but Nine: But this Opinion is not worth confuting; ’tis so gross and obvious an Errour, that common Sense (which is a Rule in everything but Matters of Faith and Revelation) must convince the Reader, that Equality of Numbers, in every Verse which we call Heroick, was either not known, or not always practis’d, in Chaucer’s Age. It were an easie Matter to produce some thousands of his Verses, which are lame for want of half a Foot, and sometimes a whole one, and which no Pronunciation can make otherwise. We can only say, that he liv’d in the Infancy of our Poetry, and that nothing is brought to Perfection at the first. We must be Children before we grow Men. There was an Ennius, and in process of Time a Lucilius, and a Lucretius, before Virgil and Horace; even after Chaucer there was a Spencer, a Harrington, a Fairfax, before Waller and Denham were in being: And our Numbers were in their Nonage till these last appear’d.
John Dryden (1700). Preface to Fables ancient and modern: translated into verse, from Homer, Ovid, Boccace, & Chaucer: with original poems. London: Jacob Tonson.
The reason that Dryden did not believe Speght, I think, is that the latter had modernized the spelling, thus erasing many clues to the Middle English pronunciation of the words! It is ironic because this is the very thing that Chaucer had prayed should not happen in the passage that Speght quoted from Troilus and Creseyde.
We can see the problem clearly a couple of pages later in Dryden’s Preface, where he quotes a passage from Chaucer’s General Prologue to The Canterbury Tales (in Speght’s spelling) and complains that “you have likewise more than one Example of his unequal Numbers”. For example, in Speght’s spelling, the line:
Or feine things, or find words new
appears to have only eight syllables. But if we look at the 1542 edition of The Canterbury Tales, the spelling is:
Or feyne thynges, or fynde wordes newe
and with this spelling, there is little difficulty in finding ten syllables that scan.
The fact that Speght modernized Chaucer’s spelling casts some doubt on the possibility that he personally was able to scan Chaucer, for if he had known of the importance of the terminal e he would surely not have been so diligent in removing it. This suggests to me that Speght and his contemporaries in the late 16th century were still aware that Chaucer ought to scan, but no longer knew how to do it. Here’s a passage from George Gascoigne giving a similar impression:
Also our father Chaucer hath used the same libertie in féete and measures that the Latinists do use: and who so ever do peruse and well consider his workes, he shall finde that although his lines are not alwayes of one selfe same number of Syllables, yet beyng redde by one that hath understanding, the longest verse and that which hath most Syllables in it, will fall (to the eare) correspondent unto that whiche hath fewest sillables in it: and like wise that whiche hath in it fewest syllables, shal be founde yet to consist of woordes that haue suche naturall sounde, as may séeme equall in length to a verse which hath many moe sillables of lighter accentes.
George Gascoigne (1575). ‘Certayne notes of instruction in English verse’. In Edward Arber, ed. (1869). English Reprints: George Gascoigne, p. 34. London: 5 Queen Square, Bloomsbury.
In the same year as Dryden, Samuel Wesley published a similar account:
Of Chaucer’s Verse we scarce the Measures know,
So rough the Lines, and so unequal flow;
Whether by Injury of Time defac’d,
Or careless at the first, and writ in haste;
Or coursly, like old Ennius, he design’d
What After-days have polish’d and refin’d.
Samuel Wesley (1700). An Epistle to a Friend Concerning Poetry, p. 12. London: Charles Harper.
The comparison of Chaucer to Ennius, the “father of Roman poetry”, was a commonplace, for example Aston Cokayne called Chaucer “our true Ennius, whose old book / Hath taught our Nation so to Poetize” (‘A Remedy for Love’, 1658). Wesley, unlike Dryden, does realize that the difficulties may be due to “injury of time” (that is, to change of language) rather than incompetence of the poet.
A couple of decades after Dryden and Wesley, John Urry repeated Speght’s claim but affirmed Dryden’s skepticism. Chaucer’s pronunciation must have been truly lost at this point.
It is thought by some that his Verses every where consist of an equal number of feet; and that if read with a right accent, are no where deficient; but those nice discerning Persons would find it difficult, with all their straining and working, to spin out some of his Verses into a meafure of ten Syllables. He was not altogether regardless of his Numbers; but his thoughts were more intent upon solid sense than gingle, and he tells us plainly that we must not expect regularity in all his Verses.†
John Urry (1721). Preface to The Works of Geoffrey Chaucer. London: Bernard Lintot.
† The House of Fame, book III: “Yet make it somwhat agreable / Though some verse fayle in a syllable.”
(With thanks to Peter Shor, who found the passage from Dryden.)