As of 2014, a record 63.2 million U.S. residents over the age of five spoke a language other than English at home, up 1.4 million from the previous year and up 16.2 million from 2000, according to a new report released Tuesday by the Center for Immigration Studies (CIS). That means that as a share of the total U.S. population, more than one in five residents now speak a foreign language at home.

The fastest growing between 2010 and 2014 were speakers of Arabic, with a 29.2 percent increase. In second was Pakistan's national language of Urdu, with a 22.8 percent increase, followed by Hindi with an 18.8 percent increase and Chinese with an 11.8 percent increase.

Spanish speakers are the largest group, with 39.2 million speakers, an increase of 2.3 million from 2010. Chinese speakers were the second largest with 3.1 million speakers, an increase of about 330,000, followed by Tagalog with 1.7 million speakers and Vietnamese with 1.5 million.

North Dakota had the largest percentage increase of foreign speakers, up 18 percent, followed by Wyoming with 15 percent and Nevada with 14 percent.

Forty-one percent of people who speak a foreign language at home, or 25.6 million, said they speak English "less than very well."

Almost half of those who don't speak English at home, 28 million, were born in the United States.

"These numbers are a stark reminder that immigration is not just an economic issue. A common language is part of the glue that holds our country together," said Steven Camarota, CIS director of research and author of the report. "After the last great wave of immigration more than a century ago, the level of immigration was reduced and remained low for about half a century. This certainly helped with assimilation. But with no pause in immigration levels in sight, the nation is headed into uncharted territory."

From 1970 to 2010, America's foreign-born population increased from 9.6 million to 40 million, according to a Pew Research report.

"Between 1965 and 2015, new immigrants, their children and their grandchildren accounted for 55 percent of U.S. population growth. They added 72 million people to the nation's population as it grew from 193 million in 1965 to 324 million in 2015," said Pew.

Between 2015 and 2065, future immigrants and their descendants "are projected to account for 88% of the U.S. population increase, or 103 million people, as the nation grows to 441 million."