According to employment conditions drawn up by new transport operator Keolis and reviewed by Sveriges Radio (SR), the firm planned to impose its Swedish-only conditions to cover all interaction on its premises, including lunches and breaks.
Keolis, which takes over the running of bus services in the town in the summer from Arriva, argued that the initiative has been taken to counter discrimination.
"To enable everyone to participate in the workplace all have to be able to understand each other," said Mats Freding at the firm to SR.
Freding pointed out that non-compliance could in theory mean the sack.
"Ultimately, you can get fired if you do not follow the terms of conduct," he said.
But now the firm's leadership has argued that the local Jönköping initiative is not supported by corporate policy.
"It is not supported by the the company leadership," Keolis' director of communications Helena Reinhagen said on Tuesday afternoon.
"The well-meaning thought behind this local initiative was to create a good atmosphere in the workplace, but it has been misguided. Naturally you are able to speak the language which is best suited to the situation," she said.
SR's report on Tuesday morning prompted criticism from some quarters, including Social Democrat MP Peter Persson.
"It is beyond me," he said.
But on hearing of the employment conditions, the Kommunal union did not find anything in the new contracts that it would consider to be objectionable.
Union head Thor Tärnbring argued to SR that it is a problem when several languages are spoken at once, especially in the staff canteen.
"It would be a racket when four or five languages are mixed up and no one can get any peace and quiet, it would become a mix of everything," he said, claiming that foreign languages tend to be more flamboyantly expressed than Swedish.
"If you come from abroad, you are perhaps used to more sweeping gestures. Take the Italians for example, speaking loudly and extravagantly - then it would be more of a disturbance," he said.
The Equality Ombudsman (DO) told SR that the condition would appear to be dubious and would look into the matter if it received a report.