Language is a system that contains small elements that can be combined in an infinite number of ways in order to make larger structures. Human language has four universals: phonology, morphology, syntax, and semantics. The phonology of a language is the set of its sound patterns and the rules that govern how they can be combined; these patterns and rules give the language its distinct auditory identity. Morphology is the set of units of meaning that make up the words of a language and the ways those units of meaning can be combined. Every language also has syntax, the set of rules governing the ways in which words can be combined into phrases and sentences.
Finally, the semantics of a language are the meanings that emerge from all of the previous three elements: the sounds, word meanings, and word-order patterns. Even though the phonology, morphology, syntax, and semantics of every language differ, all languages have them. On the other hand, not every language has a writing system, or orthography.
The first evidence of written records dates back only about 10,000 years; writing systems were invented in the same fashion that early civilizations invented the wheel, glass, and other sociocultural characteristics. Although orthographies also differ according to language, their invention in any society is not inevitable.
This difference is important because the four universals are naturally acquired by native speakers of a language, whereas orthography is a feature of literacy, is not natural, and needs to be taught (Peregoy & Boyle, 2005, p. 164). Pinker (2007) says, “Language is an instinct, but reading is not” (p. 14). If reading and writing were universal and inevitable, no language group would have failed to develop a writing system, but we know that many societies, even some lasting several centuries, have not. The Mississippian peoples living in Cahokia, for example, developed complex dwellings, trade, many tools, and fine works of art, but never developed a writing system. Because reading and writing are not inevitable processes even in a first language, it stands to reason that considerable energy and effort are needed to learn to do them in a new language.