Yoruba drumming is linguistic. The dundun, the hourglass tension drum, has cords that let the player alter the pitch continuously, so it reproduces the tone contours of Yoruba speech and can play recognisable words, praise names and proverbs to a listener who knows them. The bata ensemble, associated particularly with Shango and used in orisha ceremonies, has its own repertoire of oro, rhythmic phrases belonging to specific orisha and to specific moments in a ceremony. The drums used in ritual are consecrated instruments, in the Cuban tradition containing añá, a sacred force, and the drummers are initiated specialists. Devotees report recognising their own orisha's rhythm in a crowded ceremony before consciously registering it, and possession frequently follows the correct rhythm being played. The drumming is therefore not accompaniment to the ritual: it is the summons, delivered by name, in a language the listener may not consciously know they are hearing.