Going by what I've read and what I've been told...
SUPER means SUPERIMPOSE which means write text over the current scene.
SUBTITLE is the same except write the text at the bottom of the screen so you don't obscure what's showing.
TITLE means write the text on black background.
All are left-justified action elements in caps.
Just in case you're not sure, when writing foreign dialogue you don't have to worry about the translation or writing the subtitles, just note the language in parentheticals, e.g.
IVAN
(in Russian)
I hate cops.
-Derek
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My Web Page - naked women, bestial sex, and whopping big lies.