leads schizophrenics suffer from hallucination, delusion, and other symptoms which influence the language usage of these people.
2. Human brain
Human brain has a very complex structure and function because it contains billions of cells. According to Turkington and Harris 2009: 65, there are two
kinds of brain cells: glial cells 85 and nerve cells or neurons 15. Glial cells play a supportive role in brain function such as helping to remove waste products,
supplying nutrients, maintaining electrical balance, and guiding the brain’s development. Meanwhile, neurons control the body’s emotions, the activities, and
the ability to think. The brain also has a number of language-related functions controlling the
cognitive processing involved in producing or understanding language. Steinberg 1993: 182 states that the areas which have been proposed for the processing of
speaking, listening, reading, writing, and singing are mainly located at or around the Sylvian and Rolando fissures. The front part of the parietal lobe, which is
along the fissure of Rolando, is primarily involved in the processing of sensation and it may be connected with the speech and auditory areas at a deeper level. The
area in front of the Rolando fissure is mainly involved in motor functioning, and it is thus relevant to the study of speaking and writing. Wernicke’s area an area in
the upper back part of the temporal lobe, extending upwards into the parietal lobe plays a major part in the comprehension of speech. An area in the upper part of
temporal lobe, which is known as Heschl’s gyri, is the main area involved in auditory reception. Brocha’s area the lower back part of the frontal lobe is
primarily involved in the encoding of speech. Another area towards the back of the frontal lobe, which is known as Exner’s centre, may be involved in the motor
control of writing. Part of the left parietal region, which is close to Wernicke’s area, is involved in controlling manual singing. The area at the back of the
occipital lobe is used mainly for the processing of visual input.
3. Mental illness
