This question and answer indicate that when the source of a quote comes from an unverified source, we may say it's "attributed", or that it's "apocryphal". Both of these terms imply that there is some error or uncertainty in who is credited with having said the quote being referenced.
However, I have a situation where the source of a quote is known, but the original version is an idea expressed over a few paragraphs. Over time, with many retellings, the idea has been trimmed down to an efficient and snappy phrase. So, I want to give credit to the person who had the idea, but use the snappy version that people are familiar with.
Note that no one person is known to have come up with the snappier version. Each retelling always attributed whatever version to the original source. Most people assume the original person said the snappy version the first time round.
Using a generic example, I was thinking that I would add the word (paraphrased), something like this:
"A snappy quote is a short quote."
~ Joe McFamousguy (paraphrased)
But I wondered if maybe there was a standard for this kind of thing.
What's the best way to express that this is a variant or version of a quote, but that there is no uncertainty that the source is the correct one?
Best Answer
The short version is: Use quotation marks only if you are quoting someone's actual words. If you are not quoting someone's actual words, do not use quotation marks. There is no parenthetical you can add to correct for this.
In an apocryphal quote, you are quoting the actual words that are attributed to the person; for example: "I cannot tell a lie" can be quoted and attributed to "George Washington (apocryphal)". If there was a definite source for the shortened version, you could list that person's name: "Play it again, Sam" could be attributed to "Woody Allen (paraphrasing Humphrey Bogart)".
But if the paraphrase is not part of someone else's quote, you can't put it in quotation marks; in formal writing, this will be seen as sloppy; in academic writing, dishonest. Instead, you need to put it in a sentence. "Abraham Lincoln said that we got here eighty years ago" is appropriate. "We got here eighty years ago." --Abraham Lincoln (paraphrased) is not.
Depending on the specific quote you want to use, you might be able to get away, in informal writing, with an (attributed). For example: "Play it again, Sam" -- attributed to Humphrey Bogart. Who it's attributed to him by can remain unsaid. Or, if the paraphrase is close enough, you may be able to "fix" it with brackets and ellipses: "Play it [again], Sam."
But much as I hate to say it, the best solution is to use a different quote. Consciously perpetuating a misquotation, no matter how you dress it up, will lead to mistrust in your audience.