Great Vowel Shift — part 3
To conclude this series of postings on the Great Vowel Shift let’s look at the possible causes of this wholesale upheaval in the vowel system of English. The question of why the Great Vowel Shift happened can be broken down into two questions (cited from April McMahon’s article “Restructuring Renaissance English”):
1- The inception problem: what, if anything, started the whole thing off?
2- The merger problem: once the Great Vowel Shift started, is it plausible to think of it as a chain where a shift in one vowel causes another to move too, to prevent merger and loss of distinctiveness?
To start with the inception problem, as McMahon puts it, it “remains one of the most deeply entrenched differences of opinion on the Great Vowel Shift and the phonology of early modern English”. Scholars do not even agree as to which of the changes happened first. Some scholars, including the Danish linguist Otto Jespersen in the first volume of his Modern English Grammar on Historical Principles” (1909), believe that the first step in the whole chain of events was the diphthongization of the high vowels /i:/ and /u:/ (as in time and loud), which started a so-called “drag-chain” by creating a vacant position at the top of the vowel ladder. Some support for this view comes from the fact that typologically it is quite rare for a language not to have high vowels: it is certainly a gap that would need to be filled, causing further changes.
According to an alternative view, held by Luick in his two-volume Historische Grammatik der englischen Sprache (1920-1940), it was the high-mid vowels /e:/ and /o:/ (as in green and boot) that started it all by shifting upwards towards /i:/ and /u:/. This, in turn, prompted the raising of the former high vowels, thus starting a so-called “push-chain”.
Note that both views assume that phonological systems like economy, symmetry and “good margins of safety between units” (McMahon 2006: 163). If one change causes a certain gap in the system, another change is necessary to “fix it”, and then another, and so on. In other words,
“think of the vowel system as a set of slots, each occupied by a single vowel unit, one priority for speakers might be to ensure that not too many contrasts fall together or merge, lest lexical items become indistinguishable en masse.”
Of course, such a wholesale merger would have made communication difficult: feel would have been pronounced the same as file and boot as bout.
But what could have started the diphthongization of /i:/ and /u:/ or alternatively the raising of /e:/ and /o:/? Stockwell and Minkova (1988), who take Jespersen’s view of the inception of the Great Vowel Shift, saw the key to the diphthongization in the vocalization of certain Old English consonants, which resulted in “ideal” diphthongs [ij] and [uw] replacing [i:] and [u:] in certain contexts. Once this happened, the door to gradual diphthongization into [aj] and [aw] was open. Another possibility is that the high-mid vowels /e:/ and /o:/ diphthongized in certain contexts and then raised so as to create a greater distance between the starting and ending points of the glide.
To turn to the merger problem, if we adopt the “drag-chain” view of the Great Vowel Shift, it must be a desire to maintain maximum distinctiveness among vowels that propelled the chain of changes. In contrast, for the the “push-chain” view, it is the avoidance of merger that is the rationale behind it. Of course, avoidance of merger cannot be the only force behind language change: after all, languages don’t continue to proliferate vowels beyond measure. So mergers and splits must balance each other. Nor can avoidance of merger explain all the changes that fall under the heading of the Great Vowel Shift or the additional changes that happened around that time. After all, some vowels raised not one but two steps on the vowel ladder. For example, the majority of originally low-mid front vowels shifted two steps, to high: hence modern English has /i:/ not only in words like green and queen, which had Middle English high-mid front vowel and raised by a single step, but also in words like sea and, leave, which had Middle English low-mid front vowel and which raised by two steps. Importantly, a merger of two vowels happened here, creating such homophones as leek and leak.
Finally, as McMahon discusses in her article, other phonological processes that were limited to certain dialects of English at the inception of the Great Vowel Shift may have also played an important role in instigating these changes and propelling them forward. Which highlights “very clearly the relevance and, indeed, the necessity of working with detailed present-day dialect data in assessing the sahpe and chronology of histroical sound changes”. The effect of dialectal variation and dialectal phonological changes may also shed some light as to why the Great Vowel Shift happened when it did and to relate this phonological upheaval to similarly momentous social changes, such as mass migration to the southeast of England in the wake of the Black Death with a resulting “melting pot” of dialects in London; the rise of the middle class, which often hypercorrects the pronunciation in order to sound more like the upper classes; and the anti-French sentiment (as a result of the prolonged war with France), which caused hypercorrection among the upper classes who know wanted to sound “more English than French”.