WHEN YOUNG THUG exploded from Atlanta’s rap underground into national consciousness last year, there were lots of things that set him apart. There was his appearance—a 6’3″ dude in a dress is hard to miss. There was his predilection for addressing his male friends as “bae” and “hubby.” But most obvious to listeners was how hard it was to understand what he was saying. Although Young Thug’s woozy, warbling songs certainly convey his feelings, they don’t fit neatly into a rap formula focusing on intricate—or even intelligible—wordplay. 
[...]
For Young Thug and Fetty Wap and Future and Rich Homie Quan, it’s never about what these guys are saying, it’s about how they’re saying it, what they’re doing with their voices,” says Serrano. “These guys came up with a new way to talk, basically.

More here.