“A definition of language,” observed the British cultural critic, Raymond Williams, “is always, implicitly or explicitly, a definition of human beings in the world” (1977, p. 21). That is because language permeates every aspect of human experience, and creates as well as reflects images of that experience. It is almost impossible to imagine human life without it. And yet, we seldom think about it. We are oblivious of its ubiquitous presence in and around us, just as the sh is (or, is it?) unmindful of the water it is submerged in. Even those who systematically study language have not fully figured out what it is. A case in point: After brilliantly synthesizing both Western and non-Western visions of language developed through the ages, the leading French linguist and psychoanalyst, Julia Kristeva (1989, p. 329) ends her erudite book on language with the humbling phrase: “that still unknown object—language.” Without delving deep into that still unknown object, I briefly outline in this chapter my understanding of how theoretical linguists have attempted to decipher the fundamental concepts of language and how applied linguists have tried to turn some of those theoretical oncepts into applicable pedagogic precepts.