You need to talk to them and offer them some fresh veggies for treats. Spend several 15 minute sessions each day with them and talk to them and give them some treats. How old are they? When did you get them? What do you feed them?
I am thinking that your birds are wild-caught and not captive-bred and hand-fed so, best case scenario, it will take a long time for them to trust you and, to tell you the truth, I doubt it will ever happen so, if I were you, I would try to make them as comfortable as possible in a HUGE cage where they can fly and give them good food.