Unfortunately I don't speak spanish, and I don't pilot, but isn't there too much conversation going on to take any notice of what the airplane is telling them?
Having tested config warnings on the 737 hundreds of times I don't know how you could miss it. Wrong config and it sounds as soon as you advance the throttles just as in the video/audio.
Only possibility I can think of is noise cancelling headsets, and too much verbal masking the horn.