Joseph Devlin’s book from 1910, How to Speak and Write Correctly, is like many similar books in that much of its advice still has relevance and is still ignored by (or unknown to) many people who describe themselves as writers or work as writers but are not worthy of the term except in the most literal sense.
“Don’t imagine that a college education is necessary to success as a writer. Far from it. Some of our college men are dead-heads, drones, parasites on the body social, not alone useless to the world but to themselves. A person may be so ornamental that he is valueless from any other standpoint. As a general rule ornamental things serve but little purpose. A man may know so much of everything that he knows little of anything… Cant is the language of a certain class — the peculiar phraseology or dialect of a certain craft, trade or profession, and is not readily understood save by the initiated of such craft, trade or profession. It may be correct, according to the rules of grammar, but it is not universal; it is confined to certain parts and localities and is only intelligible to those for whom it is intended… Words of “learned length and thundering sound” should be avoided on all possible occasions. They proclaim shallowness of intellect and vanity of mind.”