You are absolutely correct in exercising caution. Employers should think twice and be very careful about imposing English fluency and English-only requirements in job qualifications and in the workplace, as this may constitute discrimination on the basis of race and/or national origin under Title VII of the Civil Rights Act. There are very narrow circumstances where this is permissible and I strongly recommend you do this under the direction of your employment counsel. For guidance, I would encourage you to refer to the following in “Part V: Language Issues” of EEOC’s Enforcement Guidance on National Origin Discrimination: “Generally, an English fluency or English proficiency requirement is permissible only if required for the effective performance of the position for which it is imposed.[105] An individual's lack of fluency in English may interfere with job performance in some circumstances, but not in others. For example, an individual may be sufficiently proficient in English to qualify as a research assistant but, at that point in time, may lack the fluency to qualify as a senior scientific writer who must communicate complex scientific information in English.[106] Because the degree of fluency that may be lawfully required varies from one position to the next, employers are advised to assess the level of fluency required for a job on a case-by-case basis. Applying uniform fluency requirements to a broad range of dissimilar positions or requiring a greater degree of fluency than is necessary for a position may result in a violation of Title VII.”