So that’s what I was afraid of. A dubbed audio in which the two languages are not separated. So it’s not like my example.
Getting the video with multiple audio tracks (one per language) would be ideal, but that’s not always possible.
I recently made a video to show the effects of an audio filter. I mixed the sound of rain and the sound of thunder on the same track, so they could not be separated, however, as the thunder frequencies are low and the rain frequencies extend into the high frequencies, I was able to separate the two sounds, albeit with some degradation.
In your case, both languages share the frequency range of the human voice, so I don’t know what to do in that case.