One-fifth of people in the U.S. speak a foreign language at home, according to a report being released Monday by the Center for Immigration Studies, which found Arabic and Urdu — the national language of Pakistan — among the fastest-growing. The report found that nearly half of all California school-age children speak a language other than English at home, as do a third of Texans and Nevadans, according to the report, which is based on Census Bureau numbers.