Classifying, Categorizing, and ConceptualizingLanguage begins with words, with spoken and/or written symbols. Words refer to ideas (conflict,truth), feelings (passion,warmth), things (pigs,teeth), and actions (running,). Words can indicate relationships (however,therefore,on,after) and stand for other references (these,him). Some concepts, such as the cold side of the pillow or yellow slush, have no words (at least yet), and some concepts for which there are words do not exist (such asunicornsorthe king of Boston).
We assign names (words) to ideas, events, and objects. In so doing we classify that item under a broader, more abstract, heading. We classify when we label a specific song as rap or hip-hop, blues or country. We classify when we recognize an action as a certain kind of behavior.
Say you see a number of large yellow animals on the African plain. Words allow you to distinguish between "lions", and "lionesses," between "lions" and "pumas," between a "pride" (a group) and a "pair." Without words, we might see the differences, but we could not talk about the differences. Finally, words enable us to talk about lions in general a day later, when the lions are no longer there.
Academic v. Informal DiscussionAcademic discussion relies heavily on knowledge of relevant concepts and terminology. Informal discussion is commonly about specific events in the here and now. Academic discussion deals with concepts and theories, hypotheses and ideas. Academic writers talk more generally about the world. On the street, you might talk about your nineteen-year old cousin Vinny from Detroit taking a job at Mac Donald's. Academic discussion might talk about changing rates of unemployment, demographic factors affecting occupation selection, or the expansion of the service industry.
Our Evolving LanguageThe choice of word for any concept is essentially arbitrary. Words come to have meaning by how they are used by native speakers. ("A rose by any other name," as Shakespeare noted, "would smell as sweet.")
The English language, for example, uses the letters d-o-g (and their corresponding sounds) to denote a domestic animal. French uses chien; Spanish, perro. We name animals by their shape (spoonbill), origin (great Dane), size (horsefly), color (beaver, from Old English beofor, brown), or facial expression (dodo). Animals even talk differently in different languages. In English a duck says quack quack, in Italian qua qua, in Thai gaab gaab, and in Russian krya-krya. [ For a listings of animal sounds in many languages, see "Sounds Of The World's Animals," http://www.georgetown.edu/cball/animals/animals.html. ] Note that there is no natural rational connection between most words and the ideas they represent--well, with the exception of words such as plop, whiz, and slide.
Language mirrors the history and culture of its speakers. English speakers use words that have descended from earlier forms of English (knave, from Old English: cnafa) and borrow words form other languages. We use English names for animals (cow, sheep, deer) and French names for their meat (beef, mutton,venison). We use Spanish terms for geological features of the Southwest (canyon, mesa).
Dialects often incorporate words or grammatical structures of other languages. Black English, a combination of standard English and West African languages, includes an additional aspect indicating habitual action over time (He be swimming—he has been swimming for a while, not just now, and not just once). [ See "Black English: Its History and its Role in the Education of Our Children," http://www.princeton.edu/~bclewis\blacktalk.html, and "Black English," and http://www.browneyedintelligence.org/ebonics.html. ]
Word meanings change with time—hence the need to indicate the original meaning of words when we read Shakespearean plays, written around 1600, today. Dictionaries indicate current educated usage, not what a word is supposed to mean, which explains why there have been ten editions of the Merriam-Webster Collegiate dictionary in the past hundred years.
When a word is too closely associated with a undesired meaning, it drops out of usage, as with queer (odd) or niggardly (miserly), the latter a word from the Middle English unrelated to the racial epithet derived from the Spanish for "black."
Many people lament how, or even that, the language is changing. They want to return to a "pure" form, when no one said "It is me!," "Grow the economy," or "Winston tastes good like (as against "as" ) a cigarette should." Such an attitude is, regrettably, both uninformed and hopeless. Spoken languages constantly change, as surely as the trees turn every fall. One thousand years ago, in Old English, "Happy New Millennium, Everybody" would have been: Bliss on bæm cumendum þusende îeara, Eallum!
Finally, in this Age of the Internet, we might note two other written symbols that are a part of what is in essence a written dialect of standard English: emoticons (smileys), facial expressions formed with typographic characters to communicate emotions such as humor :-) , sadness :-( or skepticism :-/ , and Internet acronyms, such as BTW (by the way), OTOH (on the other hand), and IMHO (in my humble opinion).
Inference: Reading Ideas as Well As Words
Learning to Read and Write
Choices: The Choice of Language