‘Word’ is the path-breaker of human to human Communication System. Word is deployed in the communication system either through speech or by writing down on material surfaces. These are well-known facts which need no specific mention. However, when it comes to spoken words, there comes something worth noticing: Spoken words entail sound and that makes the difference. Sound cannot be written down in normal, known platforms. Both word written and word sounded are symbols of signals.
Human Brain has two Signal Systems by which ideas, information and knowledge are received and conveyed from person to person. The two signal systems are categorized as the First Signal System and the Second Signal System.
During the course of evolution, Homo sapiens developed an extremely important addition to its nervous activity. In animals reality of the surroundings is signalized by situations and the traces they leave behind in the cerebral hemispheres of brain which come directly to the nerve cells through visual, auditory, olfactory or other receptors. This process belongs to the category of First Signal System which humans too possess by way of impressions, sensations and notions in relation to the world around, – the world that represents both the natural and the social environs. As far as humans are concerned there is a well-laid path of communication constructed by and through ‘word’ that is heard or ‘word’ that is seen in writing. That path of communication falls within the Second Signal System.
The Second Signal System is the special capability of human brain. The special capability of second signal system is of words written and or of words spoken. The knowledge the word conveys may be of impressions, sensations and notions in relation to the world around. Process of understanding the meaning and knowledge that the word conveys, either separately or jointly, depends upon the working condition of the sensory centres in the cerebral cortex of each individual human being: Idiots, imbeciles and morons may not understand the meaning and or knowledge that word represents or conveys. But an intelligent person whose sensory reactions to signals from the environs are sharp, might in all probability, understand the meaning and knowledge a word conveys with consistency as compared to morons, imbeciles and idiots.
Humans cherish the additional ability of Second Signal System of communication through words while they overtake animals, birds and every other lower specie to maim and succeed. Humans think, evaluate and invent through the magic wand of Second Signal System along with support or help from First Signal System.