Ryanair has been accused of pushing "bigoted rubbish" after publishing a questionnaire designed to weed out travellers on fake passports.
The Irish budget airline has been handing out quizzes to people aboard flights from the UK to South Africa.
It contains questions in Afrikaans, which is just one of 11 official languages in the country, and one many South Africans do not understand.
It was also imposed during white-minority rule.
Ryanair has defended the test and claims that it is used to catch those travelling on fraudulent South African passports.
"Due to the high prevalence of fraudulent South African passports, we require passengers travelling to the UK to fill out a simple questionnaire issued in Afrikaans," it said in a statement.
"If they are unable to complete this questionnaire, they will be refused travel and issued with a full refund."
Catherine Bronze, 49, and her 11-year-old son Kolby, were not allowed to to get onto their flight to go back to their home in Essex, Metro reported.
When Catherine she got to the Ryanair check-in desk at West Knock Airport in Ireland on May 22, staff handed her a copy of the questionnaire.
She told them that she did not speak Afrikaans, but was told to ‘try her best’, she claimed.
Catherine and Kolby were denied boarding passes when she got the questions wrong, it was reported.
The test has not been met warmly online.
Referring to politician and Apartheid architect Hendrik Frensch Verwoerd, one South African man wrote: "Seriously Ryanair? This is bigoted rubbish. All South Africans speak Afrikaans?
"Verwoerd would be proud of you. Its one of 11 languages in the Rainbow Nation."
Another person accused Ryanair of believing that the country was still in Apartheid, urging them to "educate yourselves".
The quiz is riddled with grammatical and spelling errors, the FT reports.
It also contains general knowledge questions about South Africa such as what is its international dialling code, what is its capital city and who is the current president of the country.
Conrad Steenkamp, the head of South Africa's Afrikaans Language Board, told the BBC that the questionnaire was "absurd".
In a statement to South Africa's Daily Maverick paper, Irish border authorities denied they require such tests.
The test is not required by UK border authorities either.
South Africa has 11 official languages: Zulu, isiXhosa, Afrikaans, Sepedi, Setswana, English, Sesotho, Xitsonga, Siswati, Tshivenda and Ndebele.
Only around 13% of South Africans spoke Afrikaans as a first language as of 2011.
