My topic today is the human brain and its relation with language.

The human brain contains an average of ten billion neurons, ог nerve cells, each of which is linked with one thousand to ten thousand other neurons. These nerve cells participate in countless electrical microcircuits which make possible thought, perception, communication, and other types of mental activity.

The outside surface of the brain, which is known as the cortex, consists of a thin wrinkled mantle of gray tissue made up of millions of neurons. This layer of the brain represents man's relatively recent evolutionary step in neurological development and is not present to a comparable degree in any other species.

Many of the cognitive abilities that distinguish humans from other mammals reside in the cortex. These cognitive abilities include sophisticated reasoning, linguistic skills and musical ability.

我今天要讲的题目是人的大脑及其与语言的关系。

人的大脑平均有100亿个神经元，或者叫做神经细胞。每个神经元与1千至1万个其他神经元相连。神经元从事着不可悉数的微电路脉冲活动，并由此产生思维、感觉、交流以及其他一些脑力活动。

大脑的外表层叫做脑皮层，脑皮层很薄，有褶皱，是一层由数以百万计的神经元组成的灰色组织。脑皮层代表着人类在其神经发展的历史长河中近期的一次进化，任何其他物种的脑皮层都无法与人类的脑皮层相提并论。

将人与其他哺乳动物区别开来的许多认知能力,如复杂的推理能力、语言技能以及音乐技能,都属于脑皮层的工作。

The brain is divided into two roughly symmetrical hemispheres, sometimes called right and left brains. The activity of the two hemispheres is coordinated by a number of interconnecting nerve pathways.

The two sides of the brain, while fairly comparable in size and form, appear to specialize in handling various tasks. Current evidence suggests that the left and right hemispheres differ in some way in their function. For example, specialized linguistic and perceptual skills are each associated with a particular hemisphere of the brain. In most individuals, the left hemisphere has primary responsibility for language, while the right hemisphere controls visual and spatial skills as well as the perception of nonlinguistic sounds and musical melodies.

整个大脑分为两个大致对称的半球，有时被称为右半脑和左半脑。一些互为连接的神经束对这两个脑半球的活动进行协调。

大脑的两个半球虽然有着相像的尺寸和形状，却各司其职。据目前所知，两个脑半球有着不同的功能。例如，语言能力和感知能力隶属于不同的半球。大多数人的左半球负责语言操作，而右半球则掌管与视觉和空间相关的技能，负责对非语言声音以及音乐旋律的感知。

Both hemispheres of the brain are involved in control over muscular activity as well as in sight and hearing. However, each hemisphere controls these activities for the opposite side of the body. Thus the right side of the brain is responible for the movement of the left arm and leg, while the left hemisphere controls the movement of the right arm and leg. This is why someone who suffers damage to the right side of the brain will exhibit paralysis on the left side of the body.

You may ask which part of the brain is responsible for linguistic communication. Although there is no final answer to this question, studies have shown that the language center is located primarily in the left hemisphere of the brain in well over 90% of right-handers, who themselves make up about 90% of the population. Although the figure is somewhat lower for left-handers, about 60%, it is clear that the left side of the brain is somehow special as far as language is concerned.

Scientists believe that left-brain dominance in linguistic functions appears to exist prior to birth. It is now known that a portion of the left brain that is crucial to language is larger in fetuses than the corresponding portion of the right brain. This asymmetry is maintained throughout life.

So much for this session. May I stop to take your questions?

大脑的两半球都掌管肌肉活动,并负责视觉和听觉活动，不过每个半球只控制身体另一侧的活动。因此右半球只负责身体左半侧的活动，左半球只负责身体右半侧的活动。这就是为什么右半球受伤者的身体左半侧会瘫痪的原因。

也许你会问，负责语言交际活动的究竟是大脑的哪一部分?这个问题虽未有最终结论，但是研究表明，占了人口总数90%的人为右利手(即惯用右手者)，而在右利手人群中 90%以上其语言中枢位于左半球。左半球有语言中枢的人在左利手(即惯用左手者)的群体中比例较低，约占60%，尽管如此，他们大脑的左半球因某种原因具有专辖语言的功能。

科学家认为，左半球具有的语言优势特征似乎在婴儿出生前就存在了。据目前所知，与语言功能密切相关的左半球，其某一部分在胎儿期就比右半球的相应部分要大一些。这种大小不对称现象将伴随人的一生。

我的报告讲完了，下面请大家提问。

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