_The established practice of the best speakers and writers_ of any
language, is the standard of grammatical accuracy in the use of that
language.

By the phrase, _established practice,_ is implied reputable, national,
and present usage. A usage becomes _good_ and _legal,_ when it has been
long and generally adopted.

_The best speakers and writers,_ or such as may be considered good
authority in the use of language, are those who are deservedly in high
estimation; speakers, distinguished for their elocution and other
literary attainments, and writers, eminent for correct taste, solid
matter, and refined manner.

In the grammar of a _perfect_ language, no rules should be admitted, but
such as are founded on fixed principles, arising out of the genius of
that language and the nature of things; but our language being
_im_-perfect, it becomes necessary, in a _practical_ treatise, like
this, to adopt some rules to direct us in the use of speech as regulated
by _custom_. If we had a permanent and surer standard than capricious
custom to regulate us in the transmission of thought, great
inconvenience would be avoided. They, however, who introduce usages
which depart from the analogy and philosophy of a language, are
conspicuous among the number of those who form that language, and have
power to control it.

Language is conventional, and not only invented, but, in its progressive
advancement, _varied_ for purposes of practical convenience. Hence it
assumes any and every form which those who make use of it choose to give
it. We are, therefore, as _rational_ and _practical_ grammarians,