English is necessary to perform the job effectively for communications with customers, coworkers, or supervisors who only speak English in emergencies or other situations in which workers must speak a common language to promote safety.
Yes, for some jobs this would be a reasonable qualification. If the job involves reading documents in English or having a front facing position with people who only speak English then this would be reasonable. For example, if you lived in Tokyo but you were working at a hotel that had mostly English speaking guests, it would make sense to have someone who could converse with them in English.
