That's an interesting essay, there, undrentide. It also explains the devoicing of /i/ and /u/ in Japanese pretty well, and that they are actually there, even if you don't really hear them. Every time I think of examples of that, the word 業務上過失致死 comes to mind, where the end just sounds like a bunch of "sh" and "ch" strung together.
Along those lines, it's interesting, although I suppose not too surprising, to see that even in English sentences where sounds seem to go missing, we're actually making at least an attempt to produce them. I'm not sure I've ever thought about it in those terms, but it makes sense now that it's been pointed out. Also, I didn't realize that all the vowels in "morning" were nasalized before reading that. Haha, I keep saying it to check, and sure enough!