In the Alberta dialect of English, there are three environments which will affect the pronuncation of the /t/ phoneme. While these pronunciations may be found to be widespread, their employment is optional and may vary on different occasions, even within the same individual and with the same word. These pronunciations are influenced by the surrounding phonological environment. Depending on the environment, the pronunciation of the /t/ may be: (1) voiceless aspirated (2) voiced or (3) changed to a glottal closure sound.
Kemp, L. (1975). The glottal closure sound in English. Calgary Working Papers in Linguistics, 1(Winter), 35-36.