Can we tell employees to not speak a different language (other than English), during work hours in the workplace?

In general, employers must allow employees to speak their native language during work hours, unless it interferes with reasonable and necessary business operations.

The EEOC (Equal Employment Opportunity Commission) is a federal agency that provides answers to questions about discrimination in the workplace related to employees on the basis of natural origin.

Examples of When the English-Only Rule Can Be Used

• Perhaps an employee communicates with customers in his native language as part of his regular job duties, but most of his co-workers only speak English. His employer could invoke the English-only rule for interoffice communications with English speaking coworkers, though also allowing him to speak his native language with workers of the same origin. This same employee would be allowed to speak his native language on personal time, such as breaks and lunch periods, or even on his personal phone.
• Communication is vital during times of crisis or emergency which threatens the safety of workers and clients. Employers can require that English-only be used to ensure the safety of people and property.
• Imagine the chaos of a company meeting where several conversations are taking place in different languages, causing key people to miss out on important collaborations. In such a circumstance, the employer may require an English-only rule during the meeting to promote efficiency and unity of purpose and that is within their legal right to do so.

Full Disclosure

Whether in English or any other language, everyone benefits by knowing the rules and the consequences for breaking them. When instituting an English-only rule, employers may not take disciplinary action against an employee for violating it, unless they have notified the employees of the rule and consequences prior to the violation. Full and upfront disclosure, such as a section in the Employee Handbook, prevents future misunderstandings.

Helpful Links:

• Language: Why do Some Employees React Negatively to Co-Workers Speaking Other Languages at Work, and How Can HR Help? – SHRM – Tips for heading off language-based conflicts
• More Workers Claiming Job Discrimination Over Language, Accents – Insurance Journal
• Language and Accent Discrimination in the Workplace – NOLO – Additional information on job-related fluency and accents