The Welsh Language Commissioner has determined that Leggett & Platt Automotive has interfered with workers' freedom to speak Welsh.
Two of the factory's employees contacted the Commissioner after they had been instructed by their employer not to speak Welsh within working hours at the Pullmaflex site in Ammanford.
Under the Welsh Language (Wales) Measure 2011, the Welsh language has official status in Wales, and people have the freedom to use Welsh with one another. The Welsh Language Commissioner may investigate allegations of interference with that freedom.
After the Commissioner decided to open a full statutory investigation, he received confirmation from the company that they had described English as the preferred language of business and had asked Welsh speakers to avoid using the Welsh language with each other within working hours.
The company said that the main reasons behind the decision were health and safety concerns and that they wanted to create an inclusive culture.
Having considered the case, the Commissioner determined that Leggett & Platt Automotive had interfered with the freedom to use Welsh.
The Welsh Language Commissioner, Aled Roberts, said: "A number of people working at the site are Welsh speakers, and it is natural that they speak Welsh with each other at work. The instruction to use English caused them to feel angry and nervous about using the language.
“The company did not submit evidence which convinced me that there were any health and safety concerns which justify the imposition of a blanket ban on the use of Welsh; and I don’t accept that the Welsh language is a barrier to inclusive culture. I am not of the view that imposing a ban on using Welsh is compatible with an inclusive culture. On the contrary, the investigation has shown that the company's instruction created the opposite effect of alienating Welsh speakers.
“It is disappointing that an international company in the twenty-first century cannot see the merits of a linguistically diverse workforce that uses the Welsh language completely naturally. To create a truly inclusive culture it is essential, in my view, for a company to have a vision that embraces, and actually celebrates, the diversity of languages spoken by its employees.”