Most of the comments, here, are taking the statement too literally. What he means is to write sentences in a way you would in normal conversation and not try to be a writer of linguistic elocution. Don't use abbreviations, long words we may not know, pretending to be Hemingway.
Too many pretend to be Hemingway when they should write like Brian Kernighan at least.
Don't use abbreviations, long words we may not know, pretending to be Hemingway.
But Hemingway is the poster-boy for a style that is the exact opposite [0]:
Basically, his style is simple, direct, and unadorned, probably as a result of his early newspaper training. He avoids the adjective whenever possible, but because he is a master at transmitting emotion without the flowery prose of his Victorian novelist predecessors, the effect is far more telling.
By the way, for anyone who's interested, Hemingway was not only a syntactic minimalist (i.e. using simple language) but also a semantic minimalist -- he chose to leave things out of his stories, which he likened to icebergs, where only the top is visible, but whose bulk can be inferred if the writer has done his job properly -- this is his so-called "Iceberg Theory" of writing [0]:
In 1923, Hemingway conceived of the idea of a new theory of writing after finishing his short story "Out of Season". In A Moveable Feast, his posthumously published memoirs about his years as a young writer in Paris, he explains: "I omitted the real end [of "Out of Season"] which was that the old man hanged himself. This was omitted on my new theory that you could omit anything ... and the omitted part would strengthen the story." In chapter sixteen of Death in the Afternoon he compares his theory about writing to an iceberg.
Too many pretend to be Hemingway when they should write like Brian Kernighan at least.