Does redundancy constitute bad grammar?
This is a question about style, or prescriptive grammar, not about linguistics.
TV Westerns used to have theme songs. One of them started as follows:
"Wyatt Earp, Wyatt Earp;
Brave, courageous, and bold ..."
Song lyrics are poetry. This example is bad poetry IMHO, because it's so redundant.
Here's a subtler example: when I hear someone say "warm temperature", it bothers me. I'd prefer to hear about "high temperature" or "warm weather". Since "warm" has the idea of temperature built into it, "warm temperature" strikes me as slightly redundant.
Redundancy is a vice in English, but it's a virtue in some other languages. "No sé nada" and "Je ne sais rien" are acceptable, but "I don't know nothing" isn't. As the Germans say: andere Leute, andere Sitten.
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"The wind was a torrent of darkness among the gusty trees.
The moon was a ghostly galleon tossed upon cloudy seas.
The road was a ribbon of moonlight over the purple moor,
And the highwayman came riding—
Riding—riding—
The highwayman came riding, up to the old inn-door. "
Sometimes redundancy makes for very beautiful poetry. At least, I think so. 
Last edited Tue Aug 1, 2017, 04:42 PM - Edit history (2)
although this is an example of repetition, which is not quite the same thing as redundancy. Since poetry is meant to be read aloud, it is like other forms of spoken language and like music in that repetition is often a virtue.
Something Bogey never said in "Capablanca" is nevertheless a motto: "Play it again, Sam." 
I think the whole poem evokes the horse's hooves...
Tlot-tlot; tlot-tlot! Had they heard it? The horsehoofs ringing clear;
Tlot-tlot; tlot-tlot, in the distance? Were they deaf that they did not hear?
Down the ribbon of moonlight, over the brow of the hill,
The highwayman came riding—
Riding—riding—
The red coats looked to their priming! She stood up, straight and still.
Tlot-tlot, in the frosty silence! Tlot-tlot, in the echoing night!
Nearer he came and nearer. Her face was like a light.
Her eyes grew wide for a moment; she drew one last deep breath,
Then her finger moved in the moonlight,
Her musket shattered the moonlight,
Shattered her breast in the moonlight and warned him—with her death.
I merely meant that poetry is a bit different from other forms of speech and writing. It follows its own rules. (Or none at all, as the case may be.) I detest redundancy in everyday speech, as: "ER Room." "MVR Report." "ATM Machine." The examples are endless.
Similarly, the gizmos that put out fires in some large laser printers are not called fire extinguishers. They look like fire extinguishers, but they are called "anti-scorching devices". That's Madison Avenue for you.
I have also seen posts and texts from people who are trying t make a point with some flair, drama, and sophistication, and end their messages with "Walla!"
It took me the longest damn time to figure out that these folks meant "Voila." (Sorry, don't know how to get the little 'reverse apostrophe' over the "a."
Anaphora, epistrophe, palilogia, and a half dozen other forms of repetition were defined by classical Greek rhetoricians. It was mentioned that repetition is an important part of many languages (South Asian, for example), but English has been deeply inflected by the Greek classics, being a central component of the liberal arts education into the 1950s, and repetition has been a "classic" English rhetorical device for ages and ages (see what I did there?).
Kills Bugs Dead--as opposed to killing bugs alive?! 
