Converse in english with children even at home and asking them to read loudly news papers and english books, with this they become more confident and can speak with out any hesitation
Give interesting English language story books to children and encourage them to read aloud. Then talk to them in English about the stories they have read. Let a child tell others in English what he read in the story. Other children may also ask questions about the story. Thus they will build vocabulary and learrn speaking in English.
By making children to speak in english daily then it will get improved in them. try to keep your children between people who dont know the other languages which your children know. then they definitely need to talk in english. so there fore their english speaking also inproves.