Workers say Whole Foods banned use of Spanish
But the company denies it has any such policy. [..] The company insists that it didn't - that it has no such policy, and that the employees were suspended for "Rude and disrespectful behavior," According to Whole Foods spokeswoman Libba Letton. Ref. Source 6
Well, an investigation should take place to determine the truth. I speak Spanish all the time at my workplace but I have an excuse, I teach it. Having said that, I don't think it is legal to forbid people from speaking another language in the workplace.