In a nutshell:
"Sign-supported speech" when someone speaks English out loud and signs at the same time. (Often used is social settings that include non-signing hearing people and Deaf people.)
"Sim-Com" is "simultaneous communication", which means signing and silently mouthing the English words at the same time. (Often used in educational settings.)
"Voicing" (which used to be called "reverse interpreting") means the interpretor receives the signed message/"utterance", and produces a verbal interpretation, including the appropriate tone and expression.
