Equal Education general secretary Tshepo Motsepe believes South Africa has a historical background in which Afrikaans has been used to exclude others.
"In this context and in the past, we have had instances of privileged Afrikaans schools using language to exclude learners, especially at a time when we should be sharing scarce educational resources and fostering integration," Motsepe said, in response to a case unfolding in court.
He said organisations such as Solidarity portray themselves as defenders of "Afrikanerdom".
"Rather than work tirelessly to foster integration and unity, [Solidarity] would rather be in court using Afrikaans as a language to advance their narrow plan of exclusion."
He said while there is space for Afrikaans schools in the country, a problem arises when language policy is used as a tool to create separation.
"The language is spoken by millions of South Africans... especially coloured people. The issue is the use of this language to exclude and discriminate against those who don't speak it. That cannot be acceptable," he explained.
Language policy has come under the spotlight following Hoërskool Overvaal's school governing body (SGB)'s court battle to overturn a Gauteng education department decision to place an additional 55 pupils at the school.
While the department has deemed the application by the Vereeniging school's SGB a way to exclude pupils who do not speak Afrikaans, the school maintains there is not enough space to accommodate the additional learners.
This despite the department's argument that provision has been made for new furniture and an English-speaking teacher to teach the extra children.
The department reiterated that it would not allow language to be used as a barrier to entry by the high school.
"Language cannot be used as a tool to segregate learners in violation of the Constitution, the Schools' Act, the Gauteng Schools Education Act and the Gauteng admission policy," the department said in its answering affidavit.
"What is lacking is the full realisation of this policy, by this I mean the implementation and investment in African languages that will aid the development and publications of books."
Motsepe said while the department was doing its best to create a learning environment that fits South Africa's demographic, there should be greater strides towards introducing African indigenous languages at schools.
"What is lacking is the full realisation of this policy –– by this I mean the implementation and investment in African languages that will aid the development and publications of books," he said.
He reiterated the importance of children being taught in their mother tongue.
"It is vital for the overall development of the child –– this ensures adequate cognitive development and it aids the learning of other languages."
Education expert for Solidarity's School Support Centre, Melanie Buys, told HuffPost that Afrikaans was not being used to exclude learners.
"I do not think it is used as a tool to exclude others," she said.
She, however, emphasised that it is important for the department to find ways to ensure that learners are taught in their mother tongue.
"The PIRLS report also supported the importance of learning in your mother tongue because it showed that children cannot read for understanding."
She also said the department was not building enough schools and that everyone should be afforded a quality education.