French Americans are U.S. citizens or nationals of French descent and heritage. The majority of Franco-American families did not arrive directly from France, but rather settled French territories in the New World (primarily in the 17th and 18th centuries) before moving or being forced to move to the United States later on (see Quebec diaspora and Great Upheaval). Also, the largest French territory in North America was sold to the U.S., absorbing their French citizens (see Louisiana Purchase). About thirteen million U.S. residents are of French descent, and about 1.5 million of them speak the French language at home. Being isolated, mixed with different cultures, or ignored, the French-Americans developed particular cultures that reflect varying degrees of adaptation of their environments.