What are natural barriers to international trade?

"International trade is carried out by both businesses and governments—as long as no one puts up trade barriers. In general, trade barriers keep firms from selling to one another in foreign markets. The major obstacles to international trade are natural barriers, tariff barriers, and nontariff barriers. Natural barriers to trade can be either physical or cultural. For instance, even though raising beef in the relative warmth of Argentina may cost less than raising beef in the bitter cold of Siberia, the cost of shipping the beef from South America to Siberia might drive the price too high. Distance is thus one of the natural barriers to international trade. Language is another natural trade barrier. People who can’t communicate effectively may not be able to negotiate trade agreements or may ship the wrong goods."