[单项选择] Some things we know about language 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. There is no race of men anywhere on earth so backward that it has no language, no set of speech sounds by which the people communicate with one mother. Furthermore, in historical times, there has never been a race of men without a language. Second, there is no such thing as a primitive language. There are many people whose cultures are undeveloped, who are, as we say, uncivilized, but the languages they speak are not primitive. In all known 1anguages we can see complexities that must have been tens of thousands of years in developing. This has not always been well understood; indeed, the direct contrary has often been stated. Popular ideas of the language of the American Indians will illustrate. Many people have supposed that the Indians comm
A. grammar.
B. pronunciation.
C. vocabulary.
D. intonation.