Finally, as he or she goes to express which type of furniture he or she means to buy, he or she uses "couch" to denote an informal piece of furniture and "sofa" to denote a formal one. If others have different interpretations of these two words, then they will have trouble understanding what this buyer wants to purchase. Thus, language and the diversity of language greatly impact the critical thinking process. People assign linguistic terms to objects, ideas, and abstractions, which impacts how they are characterized in a person's mind. In addition, these characterizations affect the expression of one's thoughts, limiting that expression. These expressions are limited because no two people have the exact same understanding of different words and phrases. Each word or phrase has, for each individual person, a repertoire of childhood memories, connotations, associations, etc. Thus, it is never possible to be sure that what you are expressing is what others perceive. The best example of the importance of this issue is derived using idea words, such as racism and sexism. For one person, racism may bring up memories of class history books, documentaries, and a one-time accusation of being racist. Another person might have a closer relationship with the word, a person who has many times been a victim of racism. Thus, when these two people discuss racism, they discuss different things. Their expressions are limited because they are not able to fully explain to another what they mean, as each and every word has different connotations, and even denotations, for different people. This is even...

One person may think "sofa" is the less formal of the two words because her mother always called the less elegant pieces of furniture "sofas." When this person's friend refers to a "sofa" in her aunt's newly furnished parlor, her expression is limited as her friend does not quite understand what a "sofa" is.
Finally, language affects not only critical thinking and expression, but also persuasion. Because words have different connotations, using words with positive, emotional connotations often aid in the persuasion process. Examining the presidential speeches given before wars or just after wars have been declared is an excellent case study. One can quickly find that language is used to group positive and emotional words with words depicting war in order to encourage those hearing the speech to have a more favorable attitude towards war. Another example, once again, can be drawn from the classified advertisement example. The aim of a classified advertisement is to convince the audience to make a purchase. While both of the previously detailed advertisements could be describing the same item, the one that describes the piece of furniture as a "deluxe sofa" is more persuasive because of the use of a descriptive adjective and the positive connotation of the word "sofa."

Based on the fact that language plays such an important role in critical thinking, expression, and persuasion, one can draw the conclusion that language is a fundamental part of being human. Language is not simply used to describe an idea; language is an idea itself.