 The Canadian shift was first described by Clark, Elms and Yusuf in 1995 as a chain shift of vowels. Although it is primarily common in Canadian English, it can also be found in some other dialects, like the younger Pacific Northwest English. The Canadian shift typically affects the front vowels e, e and e. However, whereas the lowering and retraction of the tongue in short e is an undisputed feature of the Canadian shift, the lowering of e and e is controversial. The whole process is caused by the lower back merger, one result of which is that the lower back region of the vowel space is now less densely occupied. This again allows the lower front vowel to retract to a low-central articulation. Examples can be found in words like pack, where we can see a lowering and retraction to r, resulting in pack. Just listen. I usually spoke about half a pack. Rushing home, driving like maniacs. The Canadian shift is somehow opposite to the northern city shift, where the lower back r advances to a low-central position. Thus the word stack in Canada is pronounced the same vowel as in the word stock in Detroit, just across the lakes.