Secondary Audio Program (SAP) is used to provide Spanish or other language translations of English language TV content. Depending upon the content being viewed when listening to SAP, you may hear Spanish or other language translation, Audio Description, a duplicate of the primary audio, or silence.
In the U.S., SAP is used for the Spanish translation of the English content. Some shows (including the Super Bowl) have SAP for Spanish-speaking viewers.
While a commercial master can have both SAP and Audio Description, a show can only air one. This is because SAP is used both for Audio Description and for language translation.
If a blind or visually impaired individual is watching a show with Audio Description and a spot with SAP airs, they will hear the Spanish audio. The opposite is also true, if a Spanish-speaking viewer is watching a show with SAP and a spot with Audio Description airs, they will hear the Audio Description in English.
Not all broadcasters support SAP. As of 2024, fewer than 100 broadcasters in the U.S. have the ability to air commercials with SAP.