This annoying word has worked its way into American speaking-English like a cancer. It began in the 1980s with the "Valley Girls" culture displayed on network television programs. "Valley" refers to the San Fernando Valley north of Los Angeles, and close to Hollywood — ripe for satirizing.
Anyone who talks like this gets slotted into my file as an AIRHEAD…ditzy, shallow, and too lazy to use good English.
Wikipedia has this salient information to contribute:
Valley Girl (or Val, Val Gal) is a stereotype leveled at a socio-economic and ethnic class of American women who can be described as colloquial English-speaking, materialistic, self-centered, hedonistic, and often sexually promiscuous. Valspeak is also a form of this trait, based on an exaggerated version of '80s California English.
The term originally referred to the ever increasing number of semi-affluent and affluent middle-class and upper-middle class girls living in the bedroom community neighborhoods of San Fernando Valley. Due to the Valley's proximity to the Hollywood media machine, the demographic group which the term stereotyped garnered large exposure to the rest of the world. Consequently, the use became more general, and the stereotype can be found all over the United States, and also in other countries in different forms. During the 1980s and 1990s, in common with the trend in community orientation, interest, and education, the term metamorphosed into a caricature and stereotype of such women: a "ditzy" or "airhead" personality, and unapologetically "spoiled" behavior that showed more interest in shopping, personal appearance and social status than in intellectual development or personal accomplishment.
Once again, Hollywood comedy efforts have left a big stain on our language.