A Belgian auto parts supplier has ordered its workforce to speak only Dutch or risk being fired
The human resources boss at HP Pelzer, in the Belgian town of Genk, said the rule was "to avoid cliques forming".
Genk is in Belgium's Dutch-speaking Flemish region but 70% of the company's 125-strong workforce is non-Belgian.
Half of the non-Belgian workers at the company are Turkish and have complained to politicians and the union that the rule is aimed at them.
The rule will be in force at all times, including lunch breaks.
"We have people from Italy, India, Poland, Algeria here," human resources manager Geert Vermote told Reuters news agency.
"It's to avoid cliques forming here and there."
Workers found breaking the Dutch-only language rule are to be given a warning. Three warnings would lead to a worker's dismissal.
Two staff have received written warnings, Reuters said.
Mr Vermote said the "three strikes" policy applied to all of the company's rules, not just the language prohibition.
"It's really nothing other than other rules we have, such as a ban on smoking."
Belgium has seen a number of language rows between the Dutch-speaking Flemish population and the French-speaking Walloons.
If immigrants want to live in a country they should be at least willing to learn and use the local language.