I am Set to Keyboard Mode in the Access Method... What do all of these Features Do?
KEYBOARD OPTIONS:

Acceptance Time
This is the amount of time it takes for your device to accept a location you have touched and to activate the key.
Release Time
This is the amount of time it takes you to release a key and be able to activate another key. For example, if you set this for 1 second, you must wait one second after you stop touching a key before you can activate the same key or a new key.
Auto Repeat
This lets you choose how fast a key will repeat itself when you hold it down.
Warning: If this is set too low, simple key activations may allow the key to continuously repeat more than desired.
Activate Key When: Pushed or Released
Pushed means your device will activate a key when you touch it (push it in).
Released means your device will activate a key when you stop touch it.
Predictive Selection (not available on single hit overlays)
Note: Predictive Selection and Icon Prediction are only available when you are using an overlay that requires two or more hits to bring up a message. None of the default SpringBoard Lite overlays contain icon sequences. All vocabulary can be reached with a single hit.
This works hand-in-hand with Icon Prediction. (Icon Prediction is in the FEEDBACK MENU and the default is On.)
When you turn Predictive Selection On, your device highlights only those icons where messages are stored. These highlighted icons are the only keys on the keyboard that will produce a response.
You can change the color of the non-active keys to grey or white. Go to the FEEDBACK MENU, Icon Prediction and select Grey or White. Grey allows you to see the shadow of the icon on the key; white turns the entire key white so it looks blank. But if you try to select a grey or white key, nothing will happen.
Note: Icon Prediction alone allows you to press grey or white keys. The key's icon will appear in the Icon display area but no message will be spoken. Icon Prediction will work whether Predictive Selection is On or not.
Note: Remember that these two options are only available when you are using an overlay with icon sequences.