Spell Components
To cast a spell with a verbal (V) component, your character must speak in a firm voice. If you’re gagged or in the area of a silence spell, you can’t cast such a spell. A spellcaster who has been deafened has a 20% chance to spoil any spell he tries to cast if that spell has a verbal component.
To cast a spell with a somatic (S) component, you must gesture freely with at least one hand. You can’t cast a spell of this type while bound, grappling, or with both your hands full or occupied.
To cast a spell with a material (M), focus (F), or divine focus (DF) component, you have to have the proper materials, as described by the spell. Unless these components are elaborate, preparing them is a free action. For material components and focuses whose costs are not listed in the spell description, you can assume that you have them if you have your spell component pouch.