Is "in-TEST-eyen" /ɪnˈtestaɪn/ a valid pronunciation for "intestine"? I looked up "intestine" in MacMillan, Oxford, Cambridge, Merriam-Webster and even the Longman Pronunciation Dictionary, none of which recommends that pronunciation. However, I've heard at least two Canadians use it (Matthew Santoro and one of those guys on ASAP Science on YouTube). I have no access to any Canadian English dictionary.
So, is "in-TEST-eyen" /ɪnˈtestaɪn/ a valid (common and accepted as correct, not as a mispronunciation) pronunciation for "intestine"? Or is it just valid in Canada? Or did those Canadians simply mispronounce it?
This is a regional or dialectical pronunciation of the word... typical Canadian. It is no more a mispronunciation than the non-rhotic "pahh-keeng ya cahh in Bahh-sten."
One of my favorite Canadian pronunciations is for the city of Regina, Saskatchewan. It's very quaint and a bit contagious once you hear it. The vowel sounds for the i in Regina and the second i in intestine are pronounced virtually the same by many Canadians. (Long "I" like the dipthonged word "aye" or the pronoun "I")
The majority of English speakers say "reh-JEE-nah" and "in-TEST-in," both of which could be used to detect a non-Canadian accent.
We can find the linguistic expression of the Canadian east-west connection at all linguistic levels. Vowels, for instance, love to change but when they change in Canada they have been shown to rarely – for some changes never—cross the Canada-US border. For example, the ‘Canadian shift’, first detected in the mid 1990s, affects the ‘short front vowels’.....
Other features include ‘Canadian raising’, the most-widely known Canadian pronunciation feature. Canadian raising affects the diphthongs in words such as wife, price, or life and house, about, or shout. Canadian pronunciations, though far from universal, are often perceived as weef instead of wife and a boot instead of about by outsiders......
As a native Canadian who has lived in Canada for 40 years, in California for 8 years, in Texas for 6 years and in Florida for 2 years, I can say with high confidence that intestine and Regina are usually pronounced "in-TEST-(eye)n" and "ree-J(EYE)-na" in Canada. Same pronunciation for intestine most places in USA too. Sometimes intestine is pronounced like "in-TEST-in". Intestine is almost never pronounced like "in-TEST-een" except by those with foreign dialects. Regina, for anyone who associates the name with the city, is usually pronounced "Ree-J(EYE)-na" in both USA and Canada. As a woman's name, it could be pronounced either way in Canada, but most often as "Re-JEE-na" in the US, especially by foreign English speakers and hispanics.