The BIA hears appeals from certain decisions rendered by immigration judges and by district directors of the Department of Homeland Security (DHS) in a wide variety of proceedings. In addition, the BIA is responsible for the recognition of organizations and accreditation of representatives requesting permission to practice before DHS, the immigration courts, and the BIA.
The U.S. Census Bureau and the American Community Survey (ACS) maintain statistics on the linguistic composition of LEP individuals in your service area. The two main sources of data: Decennial Census and American Community Survey (ACS). There are major differences between the decennial Census and ACS (from the presentaiton Accessing and Using Language Data from the Census Bureau (PPT):