Mr Sexyloops he say
"Historically the switch cast predates spey casting. Basically the switch cast is exactly the same as the single-spey, but with one small difference: the fly does not kiss the water on the backcast."
BUT then he says
"This said, now the Switch Cast is most commonly used to refer to the Jump or Dynamic Roll. Don't you just love us flycasting instructors?"
So the tiger has a trunk..... sometimes.......... depending on who's talking.
There Ian, hopes that's cleared that up for you.
Saggyloops