Angry parents have denied they are racist because they object to their primary school children being taught to sing a song in Lithuanian.
Teachers had planned for children to perform the piece at a multi-cultural festival at Peckover Primary in Wisbech, Cambrigeshire, to reflect the fact that a third of the school's pupils are from migrant East European families.
But parents complained after their children reportedly came home in tears because they didn't understand the words of the song.
They have now launched a petition in a bid to persuade the school's head to change the song the pupils will perform.
Parents say their objection is not racist, but that their children are nervous about performing something they don't understand.
Mother Clare Eve, 48, said: "Children don't know what they are singing about but if we complain we are accused of being racist and yet this isn't the case.
"If your child is upset then surely you have the right for freedom of speech to voice your opinion."
Tamara Meldrum, who also has a child at the school, said: "They're not even teaching them what it means, at least that would make some sense, but as it stands the children have no idea why they are being forced to do it."
Mums and dads first learned about the international festival in a letter sent home inviting them to watch the performance, planned for July 15.
Principal Mrs Conant last week asked for parents' support at the 'pioneering' International Singing Festival.
The letter read: "We are all very excited to hold this event, which has been made possible by a grant from the Cambridge Culture Project Funding, for which we had managed to secure the funds.
"It will be a wonderful occasion, enabling the children to perform the songs that they have enjoyed learning and singing in English and other languages, representative of children at our school.
"We really hope you will support us in this pioneering event and look forward to seeing you all ready for a 1:45pm start."
Peckover Primary School said pupils had been taught the meaning of the Lithuanian song and children would not be forced to take part if parents objected.
A spokesperson said: "The children have spent time learning the words and understanding what they mean with the help of our excellent teaching staff and language and music specialists.
"We have made sure that children understand what they are singing about and that they learn to appreciate other cultures.
"Children have been keen and enthusiastic to take part in this inclusive community event.
"We have made alternative arrangements for pupils of parents not wishing their child to take part in the concert to remain at Peckover Primary school, for the hour during which the concert takes place."
A spokesman from Show Racism the Red Card, an anti-racism educational charity, supported the singing festival.
He said: "We believe that there is tremendous value in celebrating multiculturalism and diversity in schools".
"We accept that the Lithuanian language may present a challenge to some young people; however we are sure that the focus of the teachers is to encourage participation rather than linguistic accuracy."