The recent EAT ruling in Kelly v Covance Laboratories serves as a reminder of the discrimination risks inherent in prohibiting employees from speaking in their native (non-English) language. In this case, the employee's claim that an instruction not to use Russian was direct race discrimination failed as the employer was able to show that the reason for the instruction was security concerns (over possible infiltration by animal rights activists), rather than the nationality of the individual. The fact that employees of other nationalities were treated in the same way was helpful evidence in support of the reason being something other than race.
Employers should ensure that they have a legitimate business reason for imposing a language requirement and should consider carefully whether this justifies extending the requirement to all social conversation between work colleagues in addition to work conversations. Any policy should be made clear and applied consistently to all employees. It would also be preferable to frame the requirement as one to speak English, rather than not to speak a particular foreign language.