speech centers [AS, spaec + Gk, kentron] , either of two motor areas involved in speech. Broca’s motor speech area is a unilateral area in the posterior part of the inferior frontal gyrus and is usually on the dominant hemisphere. Wernicke’s second motor speech area is an area comprising the posterior part of the superior temporal gyrus next to the transverse temporal gyri and the supramarginal and temporal gyri, also on the dominant hemisphere. See also Broca’s area, Wernicke’s center.