In addition, there are many kinds of aphasia. The most familiar ones are Broca‟s aphasia and Wernicke‟s aphasia. Sleeper 2007:81 defines that Broca‟s
aphasia is a language disorder caused by brain damage which occurs in the frontal lobe of the left hemisphere. This damage can affect speech production. According
to Steinberg 1993:187, the speech and writing in people who suffer from Broca‟s aphasia are meaningful but shortened. The sufferers may be able to
understand spoken language but they have difficulty in grammatical inflection such as lacking the auxiliary „be‟ or the third person present tense „s‟.
According to Sleeper 2007:81, Wernicke‟s aphasia is a language disorder
caused by brain damage which is located in the temporal lobe of the left hemisphere. People who suffer from this aphasia have inability to understand the
language because they have problems in speech comprehension. They have problems in understanding what people say or what people write. They can
produce speech fluently using long sentences, but their speech is meaningless. There is also global aphasia. It is a very terrible condition because it can
affect both speech production and speech comprehension. According to Sleeper 2007:81, Global aphasia occurs when individuals have intensive damage to the
language center of the brain. People who suffer from this aphasia can have difficulty in speaking, understanding, reading and writing.
b. Dysarthria
Dysarthria has a difficulty in articulating speech because of the dysfunction of the muscles of the mouth, face and respiratory system Sleeper,
2007:85. It is also known as a neuromotor disorder because there is a disruption in the neuron system in the brain. It involves problems with the transfer of
information from the nervous system to the muscles. The transmission of messages controlling the motor movements for speech is interrupted. People who
suffer from dysarthria may have slurred and slow speech, abnormal intonation when speaking, and mumbled speech. In addition, people with dysarthria usually
also suffer from cerebral palsy, stroke, tumor and a degenerative disease such as Parkinson‟s disease Sleeper, 2007:85.
c. Apraxia
Apraxia is another disorder that affects speech. It is caused by brain injury. Sleeper 2007:86 explains that people with apraxia have difficulty in
coordinating speech. They know the words that they want to say but the sounds that they produce do not come out correctly as they intend. Sometimes, the
sufferers can produce particular sounds successfully but other times, they fail to produce the same sounds.
Apraxia also can be caused by genetic. It is known as developmental apraxia of speech. According to Sleeper 2007:86, the developmental apraxia can
occur because of a genetic basis from families who have history of language and communication disorders. The characteristic is that babies who suffer from
developmental apraxia become quiet babies. They cannot babble like normal infants and they have poor vocabulary. When they grow up, they may have
difficulty with long speech. Although they usually can understand language well, hearers can get difficulty in understanding their speech Lanier, 2010:30.
d. Schizophrenia
Schizophrenia is a mental disorder involving hallucinations, delusions and disorganized behaviour and speech Sleeper, 2007:98. The exact cause of
schizophrenia is unknown. However, most experts believe that the condition is caused by a combination of genetic and environmental factor. Schizophrenia is
divided into five types: paranoid, disorganized, catatonic, undifferentiated, and residual Sleeper, 2007:98.
According to Sleeper 2007:99, the five types of schizophrenia have different characteristics; Paranoid schizophrenia is characterized by auditory
hallucinations. Thompson 2007:50 also states that the sufferers feel haunted with the others. They feel to be threatened. Disorganized schizophrenia is a type
of schizophrenia which has problems in losing the ability to socialise with the others Thompson, 2007:50. In this case, the sufferer sometimes gets
inappropriate emotions with the situations. Catatonic schizophrenia involves disturbance in a person‟s movement. People who suffer from catatonic
schizophrenia will exhibit hyperactive movements even imitate the movements of others. Undifferentiated schizophrenia is characterized by no motivation,
imitation, and emotional responsiveness Thompson, 2007:50. The sufferer will experience imaginative play to other‟s behaviours. The last is residual
schizophrenia. According to Sleeper, it does not have appropriate symptoms because the symptoms are not ongoing.
e. Autism
