By Mobin Ibne Mokbul, 10th Grade, Dhaka, Bangladesh
How did you understand yesterday’s math lessons? Actually what makes you say, “My name is…”? If these questions always pop in your mind, keep reading to find the answer!
Can you remember your Grade-1 or 2 language lessons? You may have learned that the physical basis of language lies in the lips, the tongue, or the ear. The tongue, lips etc. are called ‘Language Organs’. Is it TRUE?? Can’t the deaf and mute people process language fully? People who have no capacity to use their vocal cords may still be able to comprehend language and use its written forms. And human sign language, which is based on visible gesture rather than the creation of sound waves, is an infinitely creative system just like spoken forms of language. Again, the basis of sign language is not in the hand, just as spoken language is not based in the lips or tongue. There are many examples of aphasics who lose both the ability to write as well as to express themselves using sign-language, yet they never lose manual dexterity in other tasks, such as sipping with a straw or tying their shoes. So while our outdated knowledge says that, ‘language’ is tongue-lip-ear-hand stuff; a neuroscientist’s perspective says that, ‘language’ is brain stuff. The language organ is MIND. Not surprisingly, the study of how our brain processes language has emerged as a special branch of modern linguistics, so called ‘Neurolinguistics’.
Keep your questions in mind! Before answering them, we must learn something about your brain… Our cerebral hemispheres are divided right down the middle into a right hemisphere and a left hemisphere. Each hemisphere appears to be specialized for some behaviors. The hemispheres communicate with each other through a thick band of 200-250 million nerve fibers called the corpus callosum. (A smaller band of nerve fibers called the anterior commissure also connects parts of the cerebral hemispheres.) In all humans, the right hemisphere controls the left side of the body; the left hemisphere controls the right side of the body. Statistics show that 90% of people are right handed, while the rest (10%) are left handed. There are few people who use each hand equally; they are ‘ambidextrous’. As each part of the cerebral hemispheres controls its opposite side of the body, damage to one side of the brain will affect the opposite side of the body too. In 95% of right-handers, the left side of the brain is dominant for language. Even in 60-70% of left-handers, the left side of brain is used for language.
Back in the 1860s and 1870s two neurologists named Paul Broca and Karl Wernicke observed that people who had damage to a particular area on the left side of the brain had speech and language problems. People with damage to these areas on the right side usually did not have any language problems. The two language areas of the brain that are important for language now bear their names, Broca’s area and Wernicke’s area. See the figure below:
(Source: The Brain and Spinal Cord SW from archive.cnx.org/contents)
Are you ready to know how different parts of the brain together process language? Let’s continue…
While processing language, both sentence understanding and creating are equally important. To understand a sentence, the brain has to break it up into different parts. The first step is to separate speech sounds from non-speech sounds. This site has not been conclusively identified in the brain. However, a particular region in the auditory cortex has been found to recognize the sounds of phonemes, or consonants, and distinguish them from non-speech. Another region analyzes tone. The next step is to understand semantics and syntax. Semantics refers to the meaning of a word. Syntax means the rules we have for combining words into phrases and sentences, and for understanding the relationship among words. Scientists are still debating different theories for how semantic and syntactic information are processed, and how they are integrated. We do know that both the anterior and posterior part of Wernicke’s area in the superior temporal gyrus are involved in processing syntax. When word lists are presented along with sentences, these parts of the brain activate only with sentences. The posterior region of Wernicke’s area also appears to be involved in processing semantic information. Interestingly, this region also has been shown to integrate speech, motion, and face processing. All of these components help us interpret speech, which is why it is easier to understand speech when watching someone than when listening only. While the role of Broca’s area is still up for debate, it is known to be involved in both language production and comprehension. The act of comprehending speech requires working, or short-term memory, as our brain keeps track of what the verb is and what it acts on in the sentence. In neurotypical people, the left side of the brain is more important in the basic processing of language. The right hemisphere, however, is engaged in interpreting prosody, or the pitch and tone of a sentence. In English, we know when a sentence is a question because the speaker raises his or her voice at the sentence’s end.
So how does this relate to remembering math lessons? All these functions aided you yesterday to understand your math lessons or even to tell your name. The processing of language is a bit complicated. Despite all of its complexity, all of these processes take place in a little fraction over half a second!
Pretty cool! Isn’t it? Not surprisingly, you have just verified the assertion of the neuroscientists, “We know more about the planets than we know about our 1.2-1.4 kg brain in our head.” Stay brainy…
To know more about the topic, scan the QR code below:
(Two website links)
1. ‘Language and the Brain’ by Prof. Edward Vajda, Western Washington University.
2. ‘Split Brain’ by Dr. Eric H Chudler, University of Washington.
3. ‘How does our brain process language?’ by Autism Reading Room.
4. Kandel ER, Shwartz JH, Jessel TM (2000). Principles of Neural Science. 4th Edition. McGraw-Hill, NY. 1414 pp.
5. Friederici A (2011). The brain basis of language processing: From structure to function. Physiol Rev 1357:1392.
I am grateful to the writers of internet resources, books, scientific articles, materials which assisted me, to write this article.