Segregation itself is defined by the European Commission against Racism and Intolerance as "the act by which a (natural or legal) person separates other persons on the basis of one of the enumerated grounds without an objective and reasonable justification, in conformity with the proposed definition of discrimination. As a result, the voluntary act of separating oneself from other persons on the basis of one of the enumerated grounds does not constitute segregation".
According to the UN Forum on Minority Issues, "The creation and development of classes and schools providing education in minority languages should not be considered impermissible segregation, if the assignment to such classes and schools is of a voluntary nature