While not a logical requirement of the preceding viewpoint, it is nonetheless
true that those subscribing to it also generally hold that the language
variety learned by the normal child is itself of complete linguistic validity.
That is, not only will the child become fluent in the prevailing language
variety, but also the variety itself, insofar as it is the regularly-used pattern of
communication of the community, possesses the linguistic range and complexity
associated with fully-formed systems. Thus, Sapir (1949) tells us that
"the gift of speech and a well-ordered language are characteristic of every
known group of human beings" (p. 1). The linguistic and anthropological
evidence is most relevant here, in that it rules out the possibility of
"primitive" or "debased" or "illogical" or "substandard" varieties (Trudgill
and Giles, 1977).