National origin discrimination occurs in the workplace when a worker is harassed or treated less favorably than their coworkers because their ancestors originate from another country. Such discrimination may occur when an employee is married or associated to one of a different national origin. It's illegal to discriminate against employees who are members of or associated with ethnic promotion group or attend schools, churches, temples, or mosques of different cultures. Non US citizens cannot legally be barred from employment if they have valid working papers. A prospect employer can give you an English test to see how well you speak in write in English, but only if they test everyone. If your English proficiency is poor, the employer must have legitimate proof that discrimination is not involved in their decision not to hire you.