"I sort of have a dream; I came, I saw, I kind of conquered"
Gabriel Doyle, who has a Ph.D. in linguistics and writes the blog Motivated Grammar, told me that "sort of"' is a "de-precision device." As Dr. Doyle put it: "The speaker is saying, 'Don't think of this as being overly accurate.' "
In other words, people throw "sort of" into their speech because they're unsure. Our language is reflecting modern life.
We sort of have stable jobs until our company outsources or downsizes. We can sort of count on Social Security in retirement. We're sort of done fighting a war in Iraq. It's my nonscientific theory that "sort of" is, in part, a linguistic manifestation of the indefiniteness we feel, a noncommittal expression for a time of rapid technological change and instability across our social structures.