Just going off what I remember, you still prepare each word spell as a Wizard would instead of being able to combine words on the fly like a Sorcerer, unless you took the Exploit that allows you to trade spells for a Point. You would be able to cast your prepared word spells as often as you have spell slots for.
The reason spontaneous casters are better with word spells is because they can make up a new spell on the fly with any combination of words they know, whereas a prepared caster is locked into his choice once he has prepared his spells.
Sorcerers also get regular spells from their Bloodline instead ofwords. Certain races can also gain extra regular spells as favored class bonuses, though your GM may tell you that you have to pick up words instead.