I have just started having this problem. I Googled around and found some of the earlier solutions. I was able to gerry-rig the system in the following way.
If you stick in, alternatively, the terms: “lover” and “teacher” as the subjects of the sentence, then it will force the translator to conjugate in the formal and informal.
For instance, today, I was trying to tell my…Parisian lover that he could cook the steaks and I would cook everything else. Lol. (I am not good at cooking steaks.) But I am new at French. When I stuck in “[Y]ou can cook the steak,” it conjugated in the formal. But when I typed, “[L]over, [amoreux] you can cook the steak,” it came back with the “tu” form of pouvoir. Because…presumably if the two of you are knocking nasties, you are on familiar terms.
Reading elsewhere that the system could be gerry-rigged by the divine pronouns thou, thee, etc., but no longer was; I tried “pastor” as a subject that might force formality. I was surprised that this didn’t work. I am a pastor’s daughter, and so MY relationship with my own pastor was informal (haha), I assumed OTHER PEOPLE would consider their relationship with THEIR pastors on a more formal basis. Nope. “Tu.”
But when I used the noun-subject “teacher,” it forced the formal verb conjugations.
But…obviously this is bullshit and could be programmed so that we could toggle for it. If Google gave a shit.