Many things about language are a mystery, and many will always remain so. But some things we do know.
First, we know that all human beings have a language of some sort.{{U}} (1) {{/U}}is no race of men anywhere on earth so backward that it has{{U}} (2) {{/U}}language, no set of speech sounds by which the people communicate with one{{U}} (3) {{/U}}. Furthermore, in historical times, there has never been a race of men{{U}} (4) {{/U}}a language.
Second, there is no such thing as a primitive language. There are many people{{U}} (5) {{/U}}cultures are underdeveloped, who are, as we say, uncivilized, but the{{U}} (6) {{/U}}they speak are not primitive. In all known languages we can see complexities{{U}} (7) {{/U}}must have been tens of thousands of years in development.
This has not{{U}} (8) {{/U}}been well understood; indeed, the direct contrary has often been stateD．Popular ideas{{U}} (9) {{/U}}the language of the American Indians will illustrate. Many people have supposed that the Indians{{U}} (10) {{/U}}in a very primitive system of noises. Study has proved this{{U}} (11) {{/U}}be nonsense. There are, or were, hundreds of American Indian languages, and all of them{{U}} (12) {{/U}}out to be very complicated and very old．They are certainly{{U}} (13) {{/U}}from the languages that most of us are familiar with, but they are{{U}} (14) {{/U}}more primitive that English and Greek.
A third thing we know about language{{U}} (15) {{/U}}that all languages are perfectly adequate. That is, each one is a perfect{{U}} (16) {{/U}}of expressing the culture of the people who speak the language.
Finally, we{{U}} (17) {{/U}}that language changes. It is natural and normal for language to change; the{{U}} (18) {{/U}}languages which do not change are the dead ones. This is easy to{{U}} (19) {{/U}}if we look backward in time. Change goes in all aspects of language.{{U}} (20) {{/U}}features change as do speech sounds, and changes in vocabulary are sometimes very extensive and may occur very rapidly. Vocabulary is the least stable part of any language.