Explanation: The existence of dialects can create advantages and disadvantages for regions within larger countries by...
ADVANTAGES: There would be a more diverse culture and the people of the country would adapt and most would learn other languages. (In Canada, most kids learn both French and English.)
DISADVANTAGES: Communication issues. Issues like that can slowly cause a divide between a large country which could evolve into major conflicts between people within the country. These issues, if fought over enough could cause the country to split or cause a civil war. <Worst Case Scenario