A Frizzle is a regularly (hard) feathered bird with curled feathers. A Frazzle (Curly) is a double Frizzled bird (has skin and feather problems, bald spots, brittle feathers, etc) A Sizzle is a Silkie with regular (hard) feathers that are curled. And a Frizzled Silkie is a Silkie with curly silkie feathering. http://www.thehatchingpost.com/sizzle.html
Silkies have soft downy like feathers all over the bodies. Frizzles are really breeds that have feathers that are curled. More like walking through a wind storm backwards. Frizzled Cochins hold that name. Sizzles is another name for a Frizzled Silkie. It is new and it makes the feathers more swept up. But they are still soft. Curlies are the ones that have the double frizzle gene. Pretty much meaning that the bird has very brital feathers and they just fall out making the bird bald and can cause health problems. Never breed a frizzle to frizzle or you will get a curly.