Shamil, many birds really enjoy chilies and other peppers...the Capsaicin/Capsicine/Capsicin, the chemical in peppers that causes our mouth, tongue and lips to burn, does not affect our feathered friends...my birds eat green/bell peppers and the several types of (hot) chilies I eat.....
Chippy is right...there is nothing that will encourage a bird to talk...if it is going to talk, it will do so of its own choice.....your friends don't know what they're talking about.....
Yes, you can let your birds out in a closed room, but understand that they will probably go to the highest point in the room.....if you do this while it is dark outside, you can close the curtains/drapes/shades, then turn the lights off to allow you to grab the bird(s), since they are not friendly with you yet.....when you grab them, be prepared to use your thumb and forefinger to control the bird & help prevent getting bitten...if you look at the pic below, with my thumb, I can control his beak...that is a relatively loose finger wrap, but if I lift my thumb slightly, I can close his beak & keep him from biting me.....you need to be careful here & exert just enough pressure to control the bird, not hurt it.....lifting my thumb slightly will allow me to prevent the bird from turning its head.....my hands are large enough to control conure & smaller sized birds with one hand, but you may want to use both hands so the bird does not try to twist out of your grip, which could be dangerous, if you were surprised by the movement and were not prepared for it.....
Good luck.....