Sometimes people say "most all" when they mean "almost all," but you shouldn't do it. Here's why.
Alan K. wrote, "There is a phrase (or pair of similar phrases, to be precise) that I have heard for years that drives me absolutely CRAZY, as it is grammatically incorrect, but I have yet to ever hear one grammatician (grammaticist?) ever address it: 'most every' or 'most all.'
To use, for example, the sentence 'Most every politician believes the president,' is clearly grammatically incorrect, and logically nonsensical. In the same breath, one is discussing MOST politicians, and then EVERY politician—two different subsets of politicians. I believe that what the users of this phrase are actually intending to say is 'ALMOST every,' which makes perfect sense.
I hear this phrase, and to a lesser extent 'most all,' to an increasing degree. Please help to nip them in the bud!"
Alan is correct. The phrase most every does arise from people shortening almost to most, which clearly seems to change the meaning. I found many admonitions against such usage in books from the early 1900s, and a few in my more recent usage books. The usage notes at Dictionary.com explain that using most to mean "almost" arose in 16th century England, and is common in informal speech but rare in edited text.