Is it wrong for my boss to tell me not to speak my native language at work?

Because you are working for the employer they can set the work standards and if language is one of the standards the employer can require your communcation be in english.

Good Luck

Your boss and employer may be violating WA's Law against Discrimination and the corresponding federal law.

From an faq of the WA's Human Rights Commission: "A rule requiring that employees speak only English on the job may violate Title VII unless an employer shows that the requirement is necessary for conducting business. If the employer believes such a rule is necessary, employees must be informed when English is required and the consequences for violating the rule." Title VII is the federal law prohibiting discrimination on several bases, including national origin. The faq is at http://www.hum.wa.gov/FAQ/FAQEEO.html . WA's Law against Discrimination generally follows the federal law and include more bases of unlawful discrimination.

Employers such as nursing home operators may require that employees speak only English when working around clients.

The HRC's website is http://www.hum.wa.gov/ .

To fall under the regulations of the HRC, a WA generally must have at least 8 employees. The number of employees needed to start EEOC's jurisdiction is higher.

Filing a complaint directly with the HRC or EEOC is free.

Perhaps your boss is not aware of the law. If you have a good relationship with him, you can discuss the matter with him. If there is a human resource office at your work, you can also file a complaint there.

You can review your specific facts with your attorney to see what legal options you may have.