Complex sentence: Under the formula, all provinces would have to approve amendments that would be relevant to provincial jurisdiction including the use of the French and English languages, but only the relevant provinces would be needed to approve amendments concerned with a particular region of Canada.
Split into simpler sentences: Under the formula, all provinces would have to approve amendments relevant to provincial jurisdiction including the use of the French and English languages. However, only the relevant provinces would be needed to approve amendments concerned with a particular region of Canada.