I started researching this when I noticed it was highly prevalent in my company. Furthermore, new people would join (from other parts of the country) and would pick up this speech pattern within days.
Certain speech patterns are very highly addictive and tend to be adopted quickly. I notice this most particularly with southern drawls (US) and regional northeastern accents (New Jersey, Long Island, Southie, Bronx, etc.). Others not so much (southwest / native American, northern plains (Wisconsin / Minnesota).
