Sports Direct may face a flood of legal claims after it was forced to apologise for putting up signs ordering staff in its UK stores to speak only English at work.
The notices said the policy included "any personal conversations" and cited "health and safety issues".
They added that staffwho failed to comply would be "subject to the disciplinary process", according to Daily Mail.
But after a sign was put up in the firm's Bangor store, critics said it was restrictive of the Welsh language.
It was written on Sports Direct headed paper and prompted Plaid Cymru AM Sian Gwenllian to say it was "discriminatory" because a lot of people speak Welsh in the area.
The notice read: "We would like to remind all staff that English is the official language of the Company and should be used at all times when carrying out Company business, unless otherwise specified.
"It has come to our attention that some members of staff are speaking in languages other than English whilst carrying out their duties.
"We would like to take this opportunity to remind staff that they must speak in English at all times when they are at work, in order that they can be understood by all members of staff.
"This includes any personal conversations that may be taking place during work time.
"Staff who fail to adhere to this Company policy may be subject to the disciplinary process."
The Welsh Language Commissioner began an investigation into the policy.
Sports Direct yesterday denied prejudice against the Welsh.
A spokesman said: "It was intended to ensure that all staff who attended briefings on health and safety and other important issues fully understood the content of these communications.
English is the most common language used by our multilingual staff and, therefore, the most likely to be understood by all."
