Schools teach students how to read and write, but not what reading and writing are — and what something is differs from how one does it. Spoken language emerges effortlessly in children. They’re so busy doing it that they don’t stop to contemplate what they’re doing, and why they’re doing it. The literary and grammatical instruction they later confront in school typically does little to spark explorations into the meaning and purpose of language.

We’re currently obsessed with school assessment, and folks properly want students to know how to read and write — even if many adults don’t do much of it themselves. So current instruction and testing focus on skills, and generally don’t explore the nature and purpose of communication.

Steven Pinker’s intriguing book, WORDS AND RULES: The Ingredients of Language (1999, Basic Books) got me to think about the why of language. His previous books were accessible, witty, and thoughtful excursions into brain matters — and this one took me on a real and joyful mental ride.

Pinker digs into a lot of the why questions by focusing principally on a single language oddity, regular and irregular verbs. Our language has many thousands of regular verbs, whose tenses we easily construct through a simple rule (walk/walked, play/played) — but fewer than 200 irregular verbs, whose tenses we must memorize since they follow no rule (send/sent, hold/held, say/said).

What’s odd is that the irregular verbs are the most frequently used. Be, have, do, and go are at the top of the verb frequency list. Why would the most frequently used words be the most difficult to master? What a fascinating question for students to explore. How tragic that the curriculum focuses so narrowly on skills that it ignores this and other intriguing questions that Pinker asks.

Language is composed of simple, familiar thoughts that individual words can represent, and complicated less familiar thoughts that require longer phrases/sentences to represent them. Pinker thus sees human language as being composed of words and rules that our brain probably processes differently, and perhaps even in different brain areas. Words are memorized links between sound and meaning, and rules are cognitive operations that combine words, and then insert additional meaning into the arrangement of the words.

Languages typically have about four dozen phonemes, about the same number of signaling sounds that primates have. The difference is that a single primate signal isn’t combined with other signals, but rather communicates a complete important idea (such as the location of food or danger).

Conversely, human language strings combinations of meaningless phonemes into sound sequences that become hundreds of thousands of meaningful words — and strings of such words into sentences and stories that are even more complex. The information in human language is thus not coded into the sounds (and letters), but rather into the sequence of the sounds/letters, and the length of the sequence (do, dog, god, good, etc.).

Music and numbers function similarly. Only twelve scale tones and ten digits can create incredibly complex forms of musical and mathematical information, because the meaning is similarly coded into the sequence and length of the chain, and not into the elements themselves. What a marvelously simple system for processing complex cognitive information.

Things get mystical. The DNA code drives biology. How can only 20 amino acids create an infinite number of proteins? Not surprisingly, the answer is that it’s the DNA-determined sequence of amino acids and the length of the chain (and not simply the amino acids) that determine a protein’s genetic information. A gene is the sequence of amino acids that form into a protein.

So we use several sequential coding systems to communicate information within our generation, and a similarly organized genetic coding system to create and maintain the children who will become the next generation. Did our brain look within its own biological coding system to create our various awesomely complex but elegantly simple communication systems? Scientists cracked the DNA code only 50 years ago, but language/music/mathematics emerged eons ago.

Rules simplify the task of adding information (such as tense or number) to a word, and Pinker suggests that our brain has an easily mastered efficient default rule system for adding suffixes to verbs and nouns. We see this when new words are added to our language. For example, when Xerox became a verb, its past tense automatically became xeroxed. Frequently used verbs may begin to drift off the rule, however, and variant forms can emerge (such as in: I am-was-will be). Genetic drifting similarly occurs in organisms over evolutionary time, creating biological diversity.

We think in categories, and use words to represent them. Categories enhance rational predictive thought processes. Some verbal categories (such as odd-number and woman) are relatively easy to define. Other categories (such as chair and vegetable) are fuzzier. Members of fuzzy verbal categories have some but not necessarily all the properties typically ascribed to the category. For example, bench, beanbag chair, sofa, stool, and wheelchair all have a sort of chair-family resemblance, but they’re quite different. Think of the members of a human family who all have the same surname, and resemble each other somewhat, but aren’t identical. We often disagree about categories, especially when we discuss the fuzzy edges of such categories as right/wrong, fair/unfair, and beautiful/ugly.

Pinker suggests that drifts into grammatical irregularity tend to occur in the fuzzier word categories. Consider the most used irregular verbs: be (existence), have (possession), do (action), and go (motion). They’re all quite fuzzy categories — difficult to define precisely, and so their tenses tended to wander off the rule over time. The result is that small children who initially use a (perhaps innate) processing rule to create runned and goed as past tenses eventually have to memorize ran and went — and about 200 other irregular verbs. Decades later, dementia may destroy their memory for irregular forms and return them to the default rule forms of runned and goed. And so it goes.

Pinker has written a thoughtful, intriguing, witty, charming book. Read it, and then tell your students what you discovered about language.