If you are hearing a second voice explaining action while watching your TV program, you likely have the SAP (Secondary Audio Channel) audio channel turned on. We often hear from viewers who are confused by this. The FCC requires television stations to provide a DVS (Descriptive Audio Service) on the main channel.
KGW is passing Descriptive Audio on the SAP audio channel whenever it is provided by NBC. When descriptive audio is not available, the SAP channel will provide a mix of the primary English audio associated with the channel.
If you are hearing the alternate audio and you do not wish to hear it.
Take a look at your remote for a button labeled MTS, SAP or Audio. Press this button one time and it should display the audio that your set is tuned to. If it shows audio 2 or Spanish, press the button again until it displays audio 1 or English, then press ENTER or OK.
If you don't find a button on your remote the SAP setting might be a menu setting. Refer to your owner’s manual to learn how to change this setting. If you have a cable or satellite receiver, please call your provider for instructions.
Additional video description information from: https://www.fcc.gov/guides/video-description