correctly is, How am I to know what words and expressions are in good use?

CONVERSATION AND GOOD USE.--Good use cannot be determined solely by
observing the conversation of our associates; for the chances are that
they use many local expressions, some slang, and possibly some vulgarisms.
"You often hear it" is not proof that an expression is in good use.

NEWSPAPERS AND GOOD USE.--Nor can good use be learned from what we
see in newspapers. Newspapers of high rank contain from time to time,
especially in their editorial columns, some of the best modern prose, and
much literature that has become standard was first printed in periodicals;
but most of the prose in newspapers is written necessarily by contributors
who do not belong to the class of "speakers or writers whom the world
deems the best." As the newspaper in its news records the life of every
day, so in its style it too frequently records the slang of daily life and
the faults of ordinary conversation. A newspaper contains bits of English
prose from hundreds of different pens, some skilled, some unskilled; and
this jumble of styles does not determine good use.

NO ONE BOOK OR WRITER DECISIVE.--Nor is good use to be learned from
our favorite author, unsupported by other authority; not even, as we have
seen, from the English Bible, when it stands alone. No writer, even the
greatest, is free from occasional errors; but these accidental slips are
not to be considered in determining good use. Good use is decided by the
prevailing usage of the writers whose works make up permanent English
literature, not by their inadvertencies. "The fact that Shakspere uses a
word, or Sir Walter Scott, or Burke, or Washington Irving, or whoever
happens to be writing earnestly in Melbourne or Sidney, does not make it
reputable. The fact that all five of these authorities use the word in
the same sense would go very far to establish the usage. On the other