English is the First or Second Language in the world this is the most useful language in the world. English is a major language of international business, diplomacy, and science and the professions.
Spanish could be very valuable for your business, studies or just for travelling. Spanish is the fourth most spoken language in the world. Namely in Central and South America, Spain and in big parts in the USA.
Italian is the fourth foreign language most spoken in U.S. homes, according to the U.S. Census Bureau. It is also spoken in Switzerland, parts of Africa, the Balkans, and the island of Malta.