Use a system of rewards. Say the desired word. Then repeat. If the bird makes a sound, reward it. Gradually become more demanding by requiring the sound to be more similar to the sound you wish them to repeat.
You can cue the bird with a question. "What is the color of money?"
"What are the color of my eyes?"
"What's your favorite color?"
Birds will also pick up on high emotion and stress. A forcefully enunciated word spoken once, very sharply and loudly, may be picked up by the bird after only one use of the word. This is why many parrots pick up on 'naughty' words!!!
A parrot can also be cued by timing. I had a small budgie who I trained to whistle the opening bars to Beethoven's Fifth each time I walked in the room by simply turning on a CD player cued to that song each time he saw me. It was a pleasant hello from a beautiful bird.