Swansea-born Christine Maguire is prepared to pursue her case to the European Court of Human Rights after she was told by the Welsh Office that the lessons were compulsory.
She claimed yesterday that to insist her children learn Welsh was an imposition by the minority of Welsh speakers in Wales on the 80 per cent who were not.
And she said the lessons left her children at a disadvantage compared with English children who had more time to concentrate on other, more important subjects such as English and maths.
Mrs Maguire, 34, a student nurse from Crynant, Neath, said: "I'm Welsh- born and bred, I'm certainly not anti-Welsh.
"If people want to learn Welsh and speak Welsh that's fine. There are plenty of opportunities. But in a democratic society, it is supposed to be majority rules, and that isn't so in Wales."
Mrs Maguire's two eldest children, Jade, 13, and Daniel 12, attend the Llangatwg Comprehensive in Neath and her younger son, Mathew, eight, goes to a local primary.
She is particularly angry for Daniel, because he had a glue ear when younger and had to work very hard to catch up on schooling he missed.
"It is a subject of no particular benefit to him. Neither myself nor my husband or my family speak Welsh and he won't use it after school," she said. "It's a struggle to learn it which he could do without. It's not really a necessary subject."
Since her complaint became known locally, she has received numerous letters of support which she has welcomed. She is now looking for advice in how to take the case further.
"In the beginning, I felt very much alone making a stand because I know how strongly some people feel about Welsh. But at the same time, my children are important to me. I've got to make a stand for them."
She said she had no regrets that although born in Wales to Welsh parents she could not speak the language herself.
A spokeswoman for the Welsh Office said Welsh was a national curriculum core subject in schools where Welsh is the main language for teaching and a foundation subject in others where it can be given up at the age of 14.
However, the law has been changed so that by the time Daniel Maguire, for example, reaches 14, Welsh will be a compulsory subject to the age of 16.
The spokeswoman said the Welsh Office had been unable to offer Mrs Maguire any advice on taking the matter to the European Court of Human Rights, but believed that the matter would not be "relevant" to that court.
The national curriculum was enshrined in law, so Mrs Maguire would have to prove that the legislation was flawed in some way, or that it infringed on her child's rights.