Yes.

Yes. And should.

Actually, the law is not that simple, and there are situations in which English-only policies are unlawful. (I will include citations to the law here since there seems to be a difference of opinion between myself and other attorneys responding to this post.)

Employer rules requiring employees to speak English at all times on the job may constitute discrimination based on national origin because “non-English speakers cannot enjoy the privilege of conversing on the job if conversation is limited to a language they cannot speak.” (Garcia v. Spun Steak Co. (9th Cir. 1993) 998 F2d 1480, 1488; see also Garcia v. Gloor (5th Cir. 1980) 618 F2d 264, 269; Maldonado v. City of Altus, Okla. (10th Cir. 2006) 433 F3d 1294, 1303 (English-only policy allegedly created hostile work environment for Hispanic workers); and 29 CFR § 1606.7 (EEOC Guideline on “English only” workplace rules).)

Such a rule may be upheld, however, where (i) justified by “business necessity” and (ii) the employees have adequate notice of the restriction. (29 CFR § 1606.7; see EEOC v. Synchro–Start Products, Inc. (ND IL 1999) 29 F.Supp.2d 911, 913.) An “English only” rule may be proper where necessary to safe and efficient operation of the business and no alternative practice will accomplish the business purpose equally as well with less discriminatory impact. This may apply, for example in work involving a high risk of injury or accidents (e.g., during surgery, or at a laboratory, oil drilling site, mining or construction site); where necessary to enable English-speaking supervisors to monitor employee communications to ensure efficient work and appropriate behavior (See 29 CFR § 1606.7); or where necessary for communication with customers, coworkers and supervisors who speak only English (See EEOC Guidance issued 12/2/02, 2002 USLW 2376).)

So to put it more simply, whether a workplace “English only” policy is unlawful depends on whether there is a legitimate business necessity, especially safety, for the policy.