Speech organs, or articulators, produce the sounds of language. Organs used for speech include the lips, teeth, alveolar ridge, hard palate, velum (soft palate), uvula, glottis and various parts of the tongue. They can be divided into two types: passive articulators and active articulators. Active articulators move relative to passive articulators, which remain still, to produce various speech sounds, in particular manners of articulation. The upper lip, teeth, alveolar ridge, hard palate, soft palate, uvula, and pharynx wall are passive articulators. The most important active articulator is the tongue as it is involved in the production of the majority of sounds. The lower lip is another active articulator. But glottis is not an active articulator because it is only a space between vocal folds.