Speech organs—or articulators—are of two types: passive articulators and active articulators. Passive articulators remain static during the articulation of sound. Upper lips, teeth, alveolar ridge, hard palate, soft palate, uvula, and pharynx wall are passive articulators. Active articulators move relative to these passive articulators to produce various speech sounds, in different manners. The most important active articulator is the tongue. The lower lip and glottis are other active articulators.