According to the National Association of the Deaf, about 37 million people in the U.S. have some type of hearing loss. For those who have a hearing impairment, closed captioning is essential for ensuring equal access to information. This tutorial covers some of the guidelines in the Captioning Key for Educational Media prepared by the National Association of the Deaf.


While closed captions are an essential aid for people with hearing impairments, captioning does not only benefit people with disabilities. Others who benefit from closed captioning include:

  • English language learners.
  • Those who are learning to read.
  • Anyone in a noisy environment such as an airport or restaurant.

There are two types of captions for videos:

  • Open captions: these captions are hard coded into the video file and area always on.
  • Closed captions: these captions are on a separate track of the video file and can be turned on and off as needed. A special CC icon is used to indicate that a video has been closed-captioned.

Some general guidelines for closed captions are as follows:

  • Try to limit captions to 2 lines to prevent the captions from blocking too much of the action shown in the video.
  • Left align captions that are 2 or more lines of text.
  • Caption as much of what is said in the video as possible. This may include captioning slang and dialect.

When the video includes more than one speaker, speaker identification is essential. The name of each speaker should appear in parenthesis, and it should be in lowercase unless you are referring to a person by his or her name.

Examples: (narrator) and (street vendor) are in lowercase but (Luis) and (Jack) are capitalized.

For sound effects, a study at Gallaudet University found that most people preferred to have both a description and the onomatopoeia in the captions. The onomatopoeia is a word that imitates the sound it represents (such as meow for the sound made by a cat). When both the description and the onomatopoeia are included in the captions, only the description should be in brackets, but both need to be lowercase.

Example: [engine idling]
rrrrrr

Italics are used in the following cases:

  • To indicate that the sound is occurring off screen. This can include background music, an off screen narrator, or off screen sound effects that are essential for understanding (such as a PA announcement, etc.).
  • To indicate that a person is dreaming, thinking or reflecting.
  • The first time a new word is defined or when using a word from a foreign language.

To indicate spelling in captions, use capital letters separated by hyphens.
Example: Luis would be captioned as L-U-I-S.

Some guidelines for when to insert line breaks are as follows:

  • Do not separate a modifier from the word it modifies.
    Example: Harry bought a black
    car. (incorrect)
    Harry bought a
    black car. (correct)
  • Do not split a sentence after a conjunction.
    Example: Jane studied for the test and
    she did well. (incorrect)
    Jane studied for the test
    and she did well. (correct)
  • Do not split a person’s first name from their last name.
    Example: Bob and Jane
    Doe were studying. (incorrect)
    Bob and Jane Doe
    were studying. (correct)

These are just a few of the guidelines suggested by the National Association of the Deaf in their Captioning Key for Educational Media. This Captioning Key is available online at http://www.dcmp.org/captioningkey/.

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