In determining what languages meet the Act’s threshold of 3 percent or 500 individuals, whichever is fewer, of the limited-English proficient (LEP) population served or encountered, or likely to be served or encountered by the District, the Language Access Program and covered entities consulted the following sources of data. 

These informational sources provided an overview of the LEP populations accounted for within the District.

• US Census: The Census Bureau serves as the leading source of quality data about the nation's people and economy.
• DC State Data Center: The US Census Bureau established the State Data Center (SDC) program in 1978 to create an effective vehicle for the dissemination of data produced by the Census Bureau to state and local governments.   
• Brookings Institution Report - Polyglot Washington - Language Needs and Abilities in the Nation's Capital: The Brookings Institution is a private, nonprofit organization devoted to independent research and innovative policy solutions. On June 21, 2004, the Institution held an event to kick off the implementation of the District’s Language Access Act during which Brookings' Audrey Singer and Jill H. Wilson released a new analysis of language use and English-speaking ability in the Washington, DC metropolitan area entitled, Polyglot Washington: Language Needs and Abilities in the Nation's Capital. This report has been used as a resource in analyzing the LEP populations’ needs that reside within the District and the Washington metropolitan region.