As I promised yesterday, this blog post will cover the rest of the game (in French). The finished speedrun is here:
I beat the game more quickly in French, despite having had less practice. I think this confirms the French conversations are faster. Kind of. The conversations are faster, if the person who's talking doesn't appear onscreen (like during phone calls, the trivet quest conversations, or whenever Nancy talks). If the person who's talking appears onscreen, it's generally the same amount of time in both languages, as they made an effort to sync the dialogue to the animations.
The main conversation in the game, where no one appears onscreen, is the ham radio challenge. Flute talks faster in English, Thisby and Pyramus talk faster in French. In English, it's fastest to call Thisby first (which takes 4:55), but in French, it's faster to call Pyramus first (which takes 4:16).
With the in-person conversations, there basically no difference between the two languages. Most of the time, Nancy has two choices of different lengths, like "No thank you" and "Actually, what I'd really like to do is talk about Josiah Crowley". It doesn't matter which language you're playing; option 1 is always going to be faster.
There's a difference between the two languages, when Emily asks Nancy to visit Jim Archer. Nancy's English options are "Sure" or "I guess". Her French options are "Avec joie" and "J'imagine". In English, the first option is about .2 seconds faster. In French, the second option is about .1 second faster. Also, the first option of the first Jim Archer conversation. In English, you select the second option, as it is .4 seconds faster. In French, the first option is .03 seconds faster.
There are other differences between the two versions. There are different solutions for the carriage door, Topham's logic puzzle and the golf poem puzzle. The phones don't ring in French, which would be a timesaver if you had to call anyone.