There are two potential real life situations here:
Add two languages when you’ve localized into two:
Your first situation is the most common situation. You have an app/website with two languages. In other words, you target two completely different sets of users. One principle for legal documents is that whenever you target a group of speakers of X (by localizing), then you need to be thinking about them being able to read the legal details as well.
Add two languages when you target another region than your home country:
Excuse me for being so generic with the title. Let’s try with a real world situation. You’ve made an app in English and everything is kept in English. You however, are based in Germany.