The Southern US accent, especially in the more rural areas, has a pronounced softening of the "s" wherever this sound appears, so that, for instance, ice cream becomes aish cream. And folks I know who were from the South, or whose families were originally from the South, and had lost all trace of their Southern accent, still retained a hint of that soft "s" so that one might think they had a slight lisp or slight speech impediment. Where did this transformation of the "s" sound come from in the US South? Why does it linger on after all other traces of the accent disappear? Why is it stronger in certain words and phrases than others?...for instance, an "sl" softens more into "schl" than an "s" softens alone at the beginning of a word? Any of our Southren linguaphiles know? Anyone else?