The best way to encourage birds to speak is to choose a few short words for them to start off with. Examples of good starter words include "hello", "bye-bye", "nite nite", or even your bird's own name.
Simple words, when said with enthusiasm, seem to become more interesting to most parrots. Make sure that when you speak to your bird, you do so in a happy, positive tone.
Watch your bird as you repeat the words you've chosen. If you pay close attention, you will probably see that some words catch his attention more than others. Use the word that your bird responds to the most for your first "training word".