The data on means of transportation to work were derived from answers to Question 25, which was asked of people who indicated in Question 23 that they worked at some time during the reference week. (See "Reference Week.") Means of transportation to work refers to the principal mode of travel or type of conveyance that the worker usually used to get from home to work during the reference week.
People who used different means of transportation on different days of the week were asked to specify the one they used most often, that is, the greatest number of days. People who used more than one means of transportation to get to work each day were asked to report the one used for the longest distance during the work trip. The category, "Car, truck, or van," includes workers using a car (including company cars but excluding taxicabs), a truck of one-ton capacity or less, or a van. The category, "Public transportation," includes workers who used a bus or trolley bus, streetcar or trolley car, subway or elevated, railroad, or ferryboat, even if each mode is not shown separately in the tabulation. "Carro público" is included in the public transportation category in Puerto Rico. The category, "Other means," includes workers who used a mode of travel that is not identified separately within the data distribution. The category, "Other means," may vary from table to table, depending on the amount of detail shown in a particular distribution. The means of transportation data for some areas may show workers using modes of public transportation that are not available in those areas (for example, subway or elevated riders in a metropolitan area where there is no subway or elevated service). This result is largely due to people who worked during the reference week at a location that was different from their usual place of work (such as people away from home on business in an area where subway service was available), and people who used more than one means of transportation each day but whose principal means was unavailable where they lived (for example, residents of nonmetropolitan areas who drove to the fringe of a metropolitan area, and took the commuter railroad most of the distance to work).

Data on language spoken at home were derived from answers to the 2007 American Community Survey Questions 13a and 13b. These questions were asked only of persons 5 years of age and older. Instructions mailed with the American Community Survey questionnaire instructed respondents to mark "Yes" on Question 13a if they sometimes or always spoke a language other than English at home, and "No" if a language was spoken only at school - or if speaking was limited to a few expressions or slang. For Question 13b, respondents printed the name of the non-English language they spoke at home. If the person spoke more than one non-English language, they reported the language spoken most often. If the language spoken most frequently could not be determined, the respondent reported the language learned first.
Questions 13a and 13b referred to languages spoken at home in an effort to measure the current use of languages other than English. This category excluded respondents who spoke a language other than English exclusively outside of the home.
Most respondents who reported speaking a language other than English also spoke English. The questions did not permit a determination of the primary language of persons who spoke both English and another language.
An automated computer system coded write-in responses to Question 13b into more than 380 detailed language categories. This automated procedure compared write-in responses with a master computer code list - which contained approximately 55,000 previously coded language names and variants - and then assigned a detailed language category to each write-in response. The computerized matching assured that identical alphabetic entries received the same code. Clerical coding categorized any write-in responses that did not match the computer dictionary. When multiple languages other than English were specified, only the first was coded.
The write-in responses represented the names people used for languages they spoke. They may not have matched the names or categories used by professional linguists. The categories used were sometimes geographic and sometimes linguistic. The following table provides an illustration of the content of the classification schemes used to present language data.
Four and Thirty-Nine Group Classifications of Languages Spoken at Home with Illustrative Examples

Four-Group Classification	Thirty-nine Group Classification	Examples
Spanish	Spanish or Spanish Creole	Spanish, Ladino, Pachuco
Other Indo-European languages	French	French, Cajun, Patois
	French Creole	Haitian Creole
	Italian	Italian
	Portuguese or Portuguese Creole	Portuguese, Papia Mentae
	German	German, Luxembourgian
	Yiddish	Yiddish
	Other West Germanic languages	Dutch, Pennsylvania Dutch, Afrikaans
	Scandinavian languages	Danish, Norwegian, Swedish
	Greek	Greek
	Russian	Russian
	Polish	Polish
	Serbo-Croatian	Serbo-Croatian, Croatian, Serbian
	Other Slavic languages	Czech, Slovak, Ukrainian
	Armenian	Armenian
	Persian	Persian
	Gujarathi	Gujarathi
	Hindi	Hindi
	Urdu	Urdu
	Other Indic languages	Bengali, Marathi, Punjabi, Romany
	Other Indo-European languages	Albanian, Gaelic, Lithuanian,Rumanian
Asian and Pacific Island languages	Chinese	Cantonese, Formosan, Mandarin
	Japanese	Japanese
	Korean	Korean
	Mon-Khmer, Cambodian	Mon-Khmer, Cambodian
	Hmong	Hmong
	Thai	Thai
	Laotian	Laotian
	Vietnamese	Vietnamese
	Other Asian languages	Dravidian languages (Malayalam, Telugu, Tamil),Turkish
	Tagalog	Tagalog
	Other Pacific Island languages	Chamorro, Hawaiian, Ilocano, Indonesian, Samoan
All other languages	Navajo	Navajo
	Other Native North American languages	Apache, Cherokee, Dakota, Pima, Yupik
	Hungarian	Hungarian
	Arabic	Arabic
	Hebrew	Hebrew
	African languages	Amharic, Ibo, Twi, Yoruba, Bantu, Swahili, Somali
	Other and unspecified languages	Syriac, Finnish, Other languages of the Americas, not reported

Respondents who reported speaking a language other than English were asked to indicate their English-speaking ability based on one of the following categories: "Very well," "Well," "Not well," or "Not at all." Ideally, the data on ability to speak English represented a person's perception of their own English-speaking ability. However, because one household member usually completes American Community Survey questionnaires, the responses may have represented the perception of another household member. Respondents were not instructed on how to interpret the response categories in Question 13c.