<P> If a specific region of the brain, or even an entire hemisphere, is injured or destroyed, its functions can sometimes be assumed by a neighboring region in the same hemisphere or the corresponding region in the other hemisphere, depending upon the area damaged and the patient's age . When injury interferes with pathways from one area to another, alternative (indirect) connections may develop to communicate information with detached areas, despite the inefficiencies . </P> <P> Broca's aphasia is a specific type of expressive aphasia and is so named due to the aphasia that results from damage or lesions to the Broca's area of the brain, that exists most commonly in the left inferior frontal hemisphere . Thus, the aphasia that develops from the lack of functioning of the Broca's area is an expressive and non-fluent aphasia . It is called' non-fluent' due the issues that arise because Broca's area is critical for language pronunciation and production . The area controls some motor aspects of speech production and articulation of thoughts to words and as such lesions to the area result in the specific non-fluent aphasia . </P> <P> Wernicke's aphasia is the result of damage to the area of the brain that is commonly in the left hemisphere above the sylvian fissure . Damage to this area causes primarily a deficit in language comprehension . While the ability to speak fluently with normal melodic intonation is spared, the language produced by a person with Wernicke's aphasia is riddled with semantic errors, and may sound nonsensical to the listener . Wernicke's aphasia is characterized by phonemic paraphasias, neologism or jargon . Another characteristic of a person with Wernicke's aphasia is that they are unconcerned by the mistakes that they are making . </P> <P> Terence Hines states that the research on brain lateralization is valid as a research program, though commercial promoters have applied it to promote subjects and products far outside the implications of the research . For example, the implications of the research have no bearing on psychological interventions such as EMDR and neurolinguistic programming, brain - training equipment, or management training . </P>

What is the function of the left hemisphere