Normans specialize in amphibious conquest and fortified border defense at once — a civilization built to land troops from the sea and then dig in permanently once they've taken ground.
"Normannitas" grants Land Units increased Movement while Embarked, and Land Units adjacent to Coast get increased Combat Strength — making coastal invasions and coastal defense both genuinely stronger than they are for any other civilization.
The Chevaler is a unique Cavalry unit that gets increased Combat Strength for every Tradition slotted in your current government, rewarding a Norman player who invests in Traditions specifically. The Sokeman is a unique Settler that automatically builds a defensive wall the moment a new Town is founded.
The Motte (Happiness on Rough terrain, counts as a Fortification) and the Bailey (Culture for adjacent walls, also a Fortification) are Norman's unique buildings, and together form the Donjon Unique Quarter, which creates a free Chevaler when built.