There are different channels (sometimes extras, called 'Sub channels) in addition to your normal locals. that's one of the nicest advantages of
DTV.
There may be some in different languages, or some may broadcast a different or more than one audio track, called 'SAP' (Second Audio Program). while most boxes have that option off by default, it may be on out of the box or it was inadvertently activated via the remote control, some of which have a button that triggers SAP on/off. try hitting that or going to the menu and turning it off and then turn off the box and then turn it back on. i don't know why but some don't remember that setting without being turned off then back on.