During some conversations, certain words are highlighted red. These are keywords which you can memorize when prompted. Select the "Memorize" command, then select the word you wish to remember with the directional buttons. Memorized words are listed in the Keywords menu.
Selecting the "Ask" command will display a list of words that you have memorized. Select the keyword you wish to ask about and press the (X) button to confirm.
Select the "Items" command to use or give an item to someone. Use the directional buttons to select an item and press the (X) button to confirm.