Why do young females today talk really squeaky?

I was watching Maury and these babies mothers talk very ghetto and fast in a high pitched voice you cant undertand a word they be saying.When did this start and originate?young adult females used to actually talk like adults,very adult like like as in expressions and pronunciation this was before the 1990's.I blame the gangsta rap culture and R&B for this cause its anoying.Like Whateva Shut cho azz up when did you start hearing this type of speaking?