
Elaine B. answered 06/02/19
Fun and Enthusiastic ESL and English Tutor
[sic] is only used when referring to written documents. According to Garner’s Usage, “it is intended to aid readers who might be confused about whether the quoter or quoted writer is responsible for the spelling or grammatical anomaly.”
It is not a device for demonstrating that you have a better grasp of grammar or spelling than the person you are quoting. Nor is it a bulletproof vest to protect against imagined criticism of sloppy proofreading. (Unfortunately I’ve seen a lot of overuse of sic for exactly those reasons in the past few years.)
If your speaker uses incorrect grammar, quote them accurately and unapologetically in your quotation format. If the meaning of the quote is too garbled to be understood by the reader, it’s perfectly fine to add clarifications [in square brackets like this] to make things clearer.