A person who is smart and studying abroad and does not speak good english.teachers apprecite him but .........

A person who is smart and studying abroad and does not speak good english.teachers apprecite him but students make him embar him. what should he do to improve his english and remain smart. means that he is shy to speak english thats y he dont speaks english and bec of that his ability and smartness is hidden. what should he do? please reply soon and thx