Experience of colombian people in the USA

Marcela is a  Colombian woman  she left her country for lived in usa but she did not speak english very well. when she came  to  USA she went out for her house to shopping center  when she was walking for the street, she saw a something fall down and she picked it up and  returned it to its  owner,  guy said thank you and she replayed   " de naikiu" (you're welcome).