Password is in the bad ending. You need to use them at the vault the day before they die, if you use it earlier it will just say it cant ressonate yet. After ressonating just keep playing and Dave will use what the vault shows him.
It usually a word that have big implication about the events that are occuring. You'll also mostly find out by observing Dave's reactions to some aspects of theses events. Not saying anything else :)
(C'est généralement un mot qui a une grande implication dans les événements en cours. Tu t'en rendra compte assez souvent en observant comment Dave réagit à certains aspects de ces événements. J'en dis pas plus :) )
Ps : non, ça va, ton Anglais n'est pas mauvais ;)
Lol, not really that surprising, actually. French is still on top 10 most common language, and one that have the most ties to (and influence on) english due to US history :)
It's just not getting a lot of spotlight when it's not about popular kind of content. But even FVN (or regular VN) have French translation sometime.
Anyway, glad you're finding out your way through the story :)