There are SO MANY lists, articles, and videos that spotlight the writer’s “don’t ever do this” language pet peeves. For added credibility, they sometimes claim to reflect “the grammar mistakes that drive your manager crazy” or “eight words that always undermine your public speaking.”
Here’s my take. There’s no definitive list of language pitfalls that is going to keep you safe from all mistakes, in all circumstances. Language evolves and changes, and one person’s pet peeve is another person’s “eh, who cares?”
Think more about your intention than a list of other people’s pet peeves. If you can connect with the audience through your message, you’ll be successful.
I do recommend that speakers check their grammar and pronunciation when they’re preparing, especially if the talk is very high stakes. More importantly, I urge audiences to suspend their reflexive judgment of other people’s misspeaking. If you hear someone use a phrase you dislike, or a word that “undermines” them, zoom out.
Everybody: focus on the whole picture, not one word or phrase.
