Airthrey Castle campus at the University of Stirling is an 18th century building primarily used as a study centre for international students.
But a sign welcoming students to the building says “Please speak English at all times, when in the castle” with a line highlighting “speak English”.
The sign has been condemned as being “insensitive” and “unwelcoming” by some.
However, the university insists it is there to encourage language students to practise their English.
But Peter Russell, 68, an art tutor at the Cowane Centre in Stirling, does not think the sign leaves a good impression to visitors at the castle.
He said: “High-handedness is not an attitude to which students respond positively.
“In the classroom, as I have stressed, this sign is a positive learning stimulant. In the foyer, it is not suitable to all users, and should, I feel, be removed.
“Potentially, visitors approaching the foyer with no prior knowledge of the language courses, and encountering such a sign they would find it off-putting, as of course would foreign students.”
Peter claims that the issue of Brexit also adds weight to this matter.
The architectural and visual art tutor also claimed that after raising the issue, an employee agreed that it wasn’t suitable.
He added: “The politics of Brexit only exacerbate this impression. Gaelic speakers, also might find the injunction a political matter too.
“In talking with a combined group of students and staff, a member of staff felt strongly that the notice was offensive to foreign students.”
An employee at Airthrey Castle claimed that the sign had been taken out of context.
She said: “The sign is in a private part of the castle. It is only for students who are here studying with English as their second language.
“We want them to get the most out of their education so we ask them to speak English when in the classroom setting.
“We wouldn’t shout at people to tell them to speak English, but they’re paying money to come here so they should want to get the most out of the opportunity to speak the language.
“We are sorry for any offence the sign caused and will change it to make sure that it is clear that it is for students only.”
A spokeswoman for the university said that the sign was put in place to encourage international students to improve their English language skills.
She said: “INTO University of Stirling, based at Airthrey Castle, is specifically tailored to offer a range of flexible and intensive English language courses, to prepare international students for their degree at the University.
“We encourage INTO students to speak English whenever possible, as it has been shown that this is the most effective way to help them to improve their language skills, in order to meet their English requirements, so that they can progress to a wide range of undergraduate and postgraduate degree options.”
The castle has previously been used as a maternity hospital between 1939 and 1968 before being taken over by Stirling University.
It was initially used for administrative and social functions but is now the institution’s school of law.