Faculty of Speech and Speech-Centers
recognize a multitude of other sounds as well and as rationally as ever.
Another kind of word-failure, or aphasia with agraphia resulting from brain injury, is common. The patient sees, hears, and understands the spoken or the written word, but he is incapable of speaking or writing it. That is to say, his motor-mechanism of speech is destroyed.
Three distinct speech-areas have been located in the brain, while a fourth exists which has not yet perhaps been found. We are conscious of words reaching us through the three special senses of sight, hearing, and touch. The visual-area is known to be in the cortex of the angular gyrus; the auditory-area is found in the first temporal convolution; the touch-area, developed in the deaf- and blind-mute, has not, I believe, been found. These are the passive or sensory areas of speech which register the incoming words. That part of the faculty of speech which is active is called the motor-center.
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