All people use language, or will learn to use it, with few exceptions. Any typical infant, who has reasonable exposure to the language of others, is sure to acquire the language(s) of its community. In fact, even in the face of most physical or intellectual challenges, language emerges.
It is undeniably true that people differ in their language abilities. Any real explanation of how language works must account for this individual variation, including both “normal” variation and disordered language. More, a complete explanation must also address how language is used for actual communication, and how well it supports other abilities that depend on it.
People in literate societies, like ours, often think of the ability to write and to read as a part of language. Many would consider these to be the most important parts of language, but they aren’t. Actually, writing and reading are “language-adjacent” skills. They come after language, and they depend on language, but they don’t come nearly as naturally or as easily as speaking and understanding speech. Language gets along just fine without writing or reading, but the opposite is not true.
Understanding the how and why of this basic truth about writing and reading, and its implications for education, is an important goal of my research.
I have more thoughts on language, reading, educational practice and policy, research, and other topics. Find them in my Blog.