Ways of blunting the assertory force of an utterance can be subsumed under the designation “linguistic anaesthetics,” in that they are discourse strategies designed to propitiate one’s interlocutor by lessening the sensitivity to potentially dangerous or harmful topics. Political correctness in language use is of a piece with this phenomenon. More specifically, two such strategies are the insertion of the word like in the speech of adolescents (particularly girls, but not only) where it has no grammatical function; and the use of interrogative intonation instead of declarative where no question is being asked (currently being labeled “uptalk”). The insertion of like is akin to the repetitive use by some adult speakers of if you like in British English and you know in all Englishes (and “you know what I’m sayin'” in Black English).
Judging by the confused way in which professional linguists interpret such usages (cf. the comments cited in the recent article “They’re, Like, Way Ahead of the Linguistic Currrve,” by Douglas Quenqua, in The New York Times, February 28, 2012, Late Edition, pp. DI-D2), there is still no general cognizance of the principle that unites them, namely what has been referred to here in earlier posts as APOTROPAISM. Strictly speaking, this term is proper to cultural anthropology, where it means the use of magic or ritual to avert evil influences, danger, or bad luck. But one can profitably apply it to ordinary language use as well.
Fillers of the sort at issue (like, I mean, you know [what I’m sayin’]) have the function of defanging or otherwise attenuating the assertory force of an utterance, in which respect they join hands naturally with the implementation of “uptalk.” The functional identity of these two strategies is revealed when one understands the interrogative intonation to share in the effect it has on the content of whatever is being uttered, since a question is necessarily but an adumbration of what the same content would be taken to be by one’s interlocutor if stated declaratively.
[Postscript: The use of three r‘s in the spelling of the last word of the title of the afore-mentioned article is an attempt to indicate a kind of vibration in the phonation of clause- and sentence-final elements in the speech of contemporary American females, called by the barbarism ‘vocal fry’. Technically, the phrase used to describe this phenomenon is ‘creaky voice’. Since creaky voice is accompanied by a diminution of acoustic energy, it can be reckoned as yet another apotropaic strategy, structurally and functionally of a piece with the disfluencies adduced for analysis above.]