There are several ways speakers have of blunting the assertory force of an utterance, including fillers (like, you know, know what I’m saying, etc.). When they edge over the line and start polluting speech, these linguistic elements are called disfluencies. One such filler that has been growing in frequency in American English is the adverb basically. More than ample recorded evidence of this word’s prominence is available in an interview with the American-Indian (Sikh) internet executive Gurbaksh Chahal (conducted on the BBC World Service by Mike Williams, November 19, 2010). Mr. Chahal, who is now 28 and speaks standard American without an accent, came to the USA at the age of four from Punjab and grew up in Northern California. Though lacking a precise count of the number of times that basically cropped up in his responses (the interview lasted 28 minutes), suffice it to say that it could not have been less that 20-30.
The frequent insertion of this word in one’s speech serves an EMOTIVE, not a referential function. The speaker is moved to attenuate the assertory force of his utterances, and in this respect the word’s appearance serves exactly the same function as one of those fulfilled by that other frequent speech pollutant, like. Whatever their primary semantic load, these words now function to qualify or deflect the force of anything being (nominally) asserted. They are thus analogous in effect segmentally to the near-ubiquitous suprasegmental feature of contemporary female speech, viz. an interrogative intonational contour on clauses that are not questions.
Like the apotropaic smile (of females in particular), any gratuitous attenuation or deflection of assertory force can be seen as an APOTROPAISM, an atavistic survival mechanism that likely has deep evolutionary roots. The emergence of a linguistic apotropaism in present-day circumstances means only that the evil being warded off need not be confined to mastodons or saber-toothed tigers: evil lurks as well in the jungles of modern life, albeit not in the form of wild beasts but in the form of fellow humans.