It is believed to have originated on the streets of Seattle as a special form of communication amongst seagulls.
Juanton: "Hand me bowlth of the poop bags. There is too much poop to fit in a single bag."
Dialect: a common regional quirk in the midwest. For some reason it seems like most St. Louisians pronounce it this way.
I had always thought StL used "television American english" but more people say "bowlth" than both in St. Louis and the surrounding counties.