The Canadian Shift is a chain shift of vowel sounds found in Canadian English, beginning among speakers in the last quarter of the 20th century and most significantly involving the lowering and backing of the front vowels. This lowering and backing is structurally identical to the California Shift reported in California English and some younger varieties of Western American English, Pacific Northwest English, and Midland American English; whether this is all a coincidence or not is still not entirely clear. The back and downward movement of all the front vowels was first noted in some California speakers in 1987, then in some Canadian speakers in 1995 , and later documented among some speakers in Western and Midland U.S. cities born after 1980, based on impressionistic analysis. Assuming the similar chain shifts found in Canada and various parts of the U.S. are a single phenomenon with a unified cause, a variety of names have been proposed for the unified, trans-regional chain shift, including the Third Dialect Shift, Elsewhere Shift, Low Back Merger Shift, and Short Front Vowel Shift.
The shift involves the lowering of the tongue in the front lax vowels , , and . It is triggered by the cot–caught merger: and merge as, a low back rounded vowel. As each space opens up, the next vowel along moves into it. Thus, the short a retracts from a near-low front position to a low central position, with a quality similar to the vowel heard in Northern England. The retraction of was independently observed in Vancouver and is more advanced for Ontarians and women than for people from the Prairies or Atlantic Canada and men. However, scholars disagree on the behaviour of and :
According to Clarke et al., who impressionistically studied the speech of a few young Ontarians, and tend to lower in the direction of and, respectively: hence, bet and bit tend to sound, respectively, like bat and bet as pronounced by a speaker without the shift.
Labov et al., through acoustic analysis of 33 subjects from all over the country, noted a backward and downward movement of in apparent time in all of Canada except the Atlantic Provinces. No movement of was detected.
Boberg considers the primary movement of and to be retraction, at least in Montreal. He studied a diverse range of English-speaking Montrealers, and found that younger speakers had a significantly retracted and compared with older speakers, but did not find that the vowels were significantly lower. A small group of young people from Ontario were also studied, and there too retraction was most evident. Under this scenario, a similar group of vowels are retracting in a parallel manner, with and approaching each other. Therefore, with Boberg's results, bet approaches but remains different from but, and bit sounds different, but remains distinct.
Hagiwara, through acoustic analysis, noted that and do not seem to be lowered in Winnipeg, although the lowering and retraction of has caused a redistribution of backness values for the front lax vowels.
Sadlier-Brown and Tamminga studied a few speakers from Vancouver and Halifax, and found the shift to be active in Halifax as well, although not as advanced as in Vancouver. For these speakers, the movement of and in apparent time was diagonal, and Halifax had diagonal movement too; in Vancouver, however, the retraction of was not accompanied by lowering.
Due to the Canadian Shift, the short-a and the short-o are shifted in opposite directions to that of the Northern Cities Shift, found across the border in the Inland Northern U.S. and Western New England, which is causing these two dialects to diverge: the Canadian short-a is very similar in quality to the Inland Northern short-o; for example, the production would be recognized as map in Canada, but mop in the Inland North.
U.S. Third Dialect Shifts
Most U.S. speakers with the cot–caught merger appear not to undergo the Canadian shift in part because typically in the U.S. the merged vowel is less rounded and/or less back and slightly lower than the Canadian vowel, and therefore less room would be left for the retraction of. In the Western U.S., one in four Western speakers in the Atlas of North American English exhibits the Canadian Shift, as defined quantitatively by Labov et al. based on the formant values for,, and. The California Shift in progress in California English contains the features of the Canadian Shift; the two phenomena may however be different, since in California the retraction of has occurred even though Californian is more centralized and less rounded than Canadian. In Pittsburgh, where cot and caught are merged to a back rounded vowel, the mouth vowel is traditionally a monophthong that fills the low central space, thus preventing from retracting. Among younger speakers, however, begins to move backward as the monophthongization of declines. Durian, via instrumental analysis, found evidence of the Canadian Shift in the vowel systems of men born circa 1965 and later in Columbus, Ohio, a city located within the U.S. Midland. is undergoing fronting without lowering, while still remaining distinct from the space occupied by. At the same time, historical is merged with the class. This allows a "free space" for the retraction of, a possibility also suggested for Western U.S. dialects being potentially capable of showing the Canadian Shift by Boberg. In Columbus, the Canadian Shift closely resembles the version found by Boberg in Montreal, where and are either merged or "close," shows retraction of the nuclei, and as well as show retraction of the nucleus.
