This report compares national distributions based on data from the American Community Survey (ACS) with those based on data from various Census Bureau surveys for three items: speaking a language other than English at home, the languages spoken, and English-speaking ability. This report first compares estimates of the number of people who reported speaking a language other than English at home. It then notes variations that are both statistically and substantially different, and for those found, it offers possible explanations. The second analysis compares specific languages spoken. The 2005 ACS data are compared with Census 2000 sample data and the Census 2000 Supplementary Survey (C2SS) data because the Census 2000 data constitute the most comparable data. The third analysis compares the English-speaking ability of respondents. The four categories of English-speaking ability are "very well," "well," "not well," and "not at all."