Thinking is interrelated not only with sensuous knowledge, but also with language and speech.
This is where we have one of the basic distinctions between the human and the animal psyche. Human thinking, whatever the form it may assume is impossible without language. Every thought evolves and develops in inseparable unity with speech.
The more elaborate of a thought, the clearer the words, both in oral and written speech that expresses it. An individual explaining something to other people and formulating his ideas make them clearer to himself.
Hence, we can very well say that language is the most efficient and developed vehicle used for carrying out the process of thinking. Both thinking and language go through regular stages of development as child grows. For many people, much of a time, a good deal of thinking involves use of words and language. That is the reason that language is considered as a tool of thought.
There is difference of opinion among psychologists regarding this idea. Some hold the opinion that, there is no difference between thought and language. They say talking and thinking are the same, thinking is self-talking, a sub-vocal speech.
JB Watson the behaviourist says that, in thinking the individual is talking to himself. He argues that children talk to themselves loudly when they are trying to solve a problem. Even adults will be whispering to themselves while thinking about a problem. It is on this ground he says that thinking is a self-talking.
But other psychologists hold the opinion that deaf people who cannot use language are able to think. They cannot speak and if thinking is self-talking they should not be able to think. But these people give evidence of thinking. Patients suffering from aphasia lose the power of speech, and their vocal organs do not function.
If thinking is self-talking there should not be any thinking in them, but they give evidence of thought. Woodworth, another famous psychologist holds that though the connection between thought and language is very intimate the two are different.
We often think of things but are not able to express our thoughts, which show that thinking goes on independently of language. While language is often used in thinking, we do not literally ‘talk to ourselves’ while thinking.
Language is described as a tool of thought, but we usually think of it as a tool of communication. Of course, communication is not limited to language. Sometimes we convey information to others non-verbally by gestures and other means.
In the light of above information, we can understand that human thinking is impossible without language.
So also our language and communication involves our ideas. Whatever we think we communicate through language whether implicit or explicit. The language and communication may be meaningless without process. Both thinking and language are closely interrelated. Whatever, we think we communicate to people. Hence, in summary what we may say is—human thinking is inseparably linked with language and communication.