According to other posts, the English-Spanish seems like a roving glitch. I'm not sure what's happening.
The Audio setting is your choice of which device to process encoded audio data: the cable-box, A/V receiver, soundbar, TV, etc.
HDMI Audio Output
3 settings: Stereo, Auto Detect (Stereo) and Expert.
Stereo is low-level processing. The cable-box will just decode the audio as 2-channel stereo sound. TV sets normally only have 2 speakers so it's good enough.
Auto Detect (Stereo) is negotiations. The cable-box will negotiate will an external device for its capabilities. "I have Stereo, Dolby Surround, Dolby Digital and Dolby Digital 5.1. Which format do you want?" After negotiating, the cable-box will decode the audio data.
Expert removes the cable-box from the decoding process altogether because...you know...it's a cheap cable-box. The keyword in the description for Expert is "...passed through..." Meaning, the cable-box will just pass the raw data to your external device and not process it.
Digital Audio Output
This setting is if you're not using an HDMI cable for audio. If you're using an HDMI cable for audio, it wouldn't affect your setup.
What other cable is there for audio? It depends on your cable-box. If your cable-box has an optical connector (SPDIF (Sony/Philips Digital InterFace))…which is an RCA or TOSLINK plug...this setting instructs your cable-box to decode the audio data as either Stereo or DD 5.1 before transmitting from the optical or SPDIF port.
