The English-speaking minority in the mainly French-speaking province of Quebec has already begun its fight against the six-day-old law increasing the predominance of French.

The largest English-language school board in Quebec voted this week to defy the French-language Charter adopted last Friday by the provincial legislature.

The Protestant School Board of Greater Montreal voted 7 to 6 to admit to its schools all non-Roman Catholic children whose parents want it, despite restrictions contained in the new language law.

Public schools in Quebec are separated by religion and are administered by either Roman Catholic or Protestant boards, with almost all the Protestant schools haveing English as theirmain language of instruction.

The Protestant Board administers 95 elementary and secondary schools with an enrollment estimated at 46,000.

The French Language Charter, generally restricts admission to the English-language schools to those children who have one parent who was educated in English in Quebec.

It allows children already attending English-language schools to continue to do so and allows their younger brothers and sisters to follow them.

Temporary residents would be permitted to enroll their children in English-language schools for as long as six years, but only if one of the parents had been educated in English.

The aim of the language restrictions is to integrate immigrants into Quebec's French-speaking majority to balance the effects of a declining birth-rate among the ethnic French.

The protestant school board also voted unanimously to allow 167 pupils who went to its schools illegally last year after failing the English tests to continue to attend them. This violates a 1974 language law.

The provincial government had warned the board that it would withhold grants for those students.

Last week Stanstead College, an English-language private school, announced that it would forego provincial funds rather than submit to the language restrictions.

Finally, the Protestant board voted unanimously to ask the federal government to seek a Supreme Court ruling on the law's constitutionality.

So far, Prime Minister Pierre Elliott Trudeau has expessed a preference for letting Quebec residents challenge it.

The English-language media in Quebec, led by two daily newspapers, have repeatedly denounced the language legislation.

Letters to the Gazette and The Montreal Star from English-speaking residents have compared Camille Laurin, minister of state for cultural development and sponsor of the language bill, to Uganda's to Idi Amin.

The two newspapers have also supported the protest by northern Quebec Eskimos against the language law.

Eight days ago the Eskinos, ordered provincial civil servants and policemen to leave four of their communities, but the order has been ignored and so far the Eskimos have not tried to enforce it.