La plume est plus forte que l'épée.
The pen is mightier than the sword.
Tu es légère comme une plume, ma chérie.
You are light as a feather, my darling.
La plume est la langue de l'âme.
The pen is the tongue of the soul.
FrenchTextbook teaches rules like this, in a full beginner course.
162 lessons, 4,000+ exercises, and 6+ hours of audio.