5 Public Speaking Mistakes That Make You Sound Less Intelligent

Mistake 1: Upspeak — Turning Statements Into Questions

You know what upspeak sounds like even if you've never heard the term. It's when someone raises their voice at the end of a declarative sentence, turning every statement into something that sounds like a question. "So we launched the project last month? And the results were really strong? And the client was super happy with the outcome?"

None of those were questions. They were supposed to be confident statements. But the rising intonation at the end — that upward lilt — makes them sound like the speaker is checking with the audience. "Is this right? Do you agree? Am I allowed to say this?" It broadcasts uncertainty, even when the speaker is completely sure of what they're saying.

Research published in the Journal of Nonverbal Behavior confirms what you'd intuitively expect: speakers who use habitual upspeak are rated as less competent, less confident, and less authoritative. And here's the kicker — the quality of their actual ideas doesn't save them. Listeners make the judgment based on delivery, not content.

I'll be honest, I didn't realize I did this until someone pointed it out. I was presenting quarterly numbers — numbers I was proud of, results I was confident about — and a colleague gently mentioned that I "sounded like I was asking permission to share good news." Ouch. But also: incredibly useful feedback.

The fix takes practice but it's not complicated. Record yourself talking about something you're sure about. Listen for the moments where your pitch rises at the end of statements. Then re-deliver those same sentences with a flat or gently falling tone at the end. The first few times it feels almost aggressive — like you're being too assertive. You're not. You're being normal. Your calibration is just off because upspeak has been your default for so long.

Quick caveat: upspeak is totally fine in actual questions, in casual conversation, and when you're checking for understanding. It only becomes a problem when it's your default mode for all speech, including statements you should be delivering with authority.

Mistake 2: Hedging and Qualifying Everything

"I'm not an expert, but..." "This might be a stupid question..." "I could be wrong, but I kind of think maybe we should possibly consider..."

Read those out loud. Feel how they land. Before you've even gotten to the actual idea, you've given your listener three reasons to dismiss it. Hedging is meant to be protective — a social shield against being wrong or seeming arrogant. But it achieves the exact opposite of protection. It invites doubt. It's like walking into a job interview and opening with "I'm probably not the best candidate, but..."

I get where it comes from. Nobody wants to be the person who states something confidently and turns out to be wrong. It feels safer to pre-qualify everything. And in some cultures and environments, hedging is even encouraged as a form of politeness or intellectual humility.

But there's a massive middle ground between arrogance and self-deprecation, and most chronic hedgers don't realize they've parked themselves way too far on the self-deprecation side.

Compare these two versions of the same idea:

• Hedged version: "I'm not sure if this is right, but I kind of think we should maybe consider changing the strategy? Like, it might not be working?"
• Direct version: "I think we should change the strategy. Here's what I'm seeing."

Same person, same idea, completely different impact. The second version isn't arrogant. It's clear. It shows you've thought about it and you have reasons.

Now, if you're genuinely uncertain — which is sometimes legitimate and even admirable to admit — express that uncertainty precisely, not vaguely. "Based on the data I've reviewed, I believe X, though I'd want to validate that with the Q3 numbers" sounds confident AND honest. "I could be totally wrong, but maybe X?" sounds like you haven't thought about it at all.

The habit to build: catch yourself mid-hedge and delete it. "I'm not an expert, but I think—" becomes "I think—." The idea stands on its own. Let it.

Mistake 3: Using Words You Don't Fully Understand

Oh, this one. I have a vivid memory of being in a college seminar and using the word "dichotomy" in a way that made zero sense. I was trying to sound smart. The professor paused, tilted her head, and said, "I don't think that word means what you think it means." I wanted the floor to swallow me.

Using big words to sound intelligent is one of the most common — and most counterproductive — speaking habits. And there's actual research proving it backfires. A delightfully titled study from Princeton called "Consequences of Erudite Vernacular Utilized Irrespective of Necessity" (yes, that title is the joke) found that people who use needlessly complex language are rated as less intelligent than those who express the same ideas simply.

Read that again. Using bigger words made people seem dumber. The researchers specifically found that simpler writing was associated with higher perceived intelligence.

Why does this happen? A few reasons. First, misusing a complex word is instantly noticeable and instantly undermining — it's like wearing a designer label with the tag still on. Second, unnecessarily complex language creates cognitive friction for the listener. They're spending mental energy decoding your word choices instead of processing your actual ideas. And third, there's something genuinely impressive about someone who can explain a complex concept in simple, clear language. It signals deep understanding rather than surface-level vocabulary.

The most articulate speakers I know follow a simple rule: use the simplest word that precisely captures your meaning. "Use" instead of "utilize." "Help" instead of "facilitate." "Start" instead of "commence." These aren't dumbed-down choices — they're clearer choices.

Now, should you expand your vocabulary? Absolutely. A bigger vocabulary gives you more precise options for specific situations. But the goal is precision, not impressiveness. Use your expanded vocabulary to say exactly what you mean, not to make people reach for a dictionary. Match your language to your audience and context. A word is only useful if it communicates — and if your listener doesn't immediately understand it, it's not communicating.

Mistake 4: Speaking Without Structure

We all know a rambler. Maybe we are the rambler. You know the type — they start answering a question and somehow end up three tangents deep, having mentioned their cousin's wedding, a documentary they watched last Tuesday, and the fact that their car needs new tires, all while the original question sits there unanswered.

Rambling is probably the single fastest way to lose your audience's attention and — crucially — their respect for your ideas. Because here's the uncomfortable truth: people equate organized speech with organized thinking. If you present ideas in a clear, logical sequence, listeners assume you think clearly. If your speech is disorganized, they assume your thinking is too. Even when it's not. Even when you have brilliant ideas buried under layers of tangent.

The human brain craves structure. When you give a listener a clear framework — "here's my point, here's why, here's an example" — their brain has filing cabinets ready. Everything you say gets organized neatly as you say it. When you ramble, their brain is scrambling to figure out what to do with each new piece of information, and eventually it gives up and tunes out.

The simplest fix is what military communicators call "bottom line up front" (BLUF). State your conclusion first. Then give the supporting details. This is the exact opposite of how most people naturally speak (we tend to narrate our thought process, building up to the conclusion), but it's dramatically more effective.

"I think we should delay the launch by two weeks because testing uncovered three critical bugs" is infinitely more powerful than "So I was looking at the testing results, and you know how Sarah's team has been working on the QA side, well they found some things, and I've been thinking about it, and..."

For anything longer than a quick answer, a three-part structure works wonders:

1. Your main point in one sentence
2. Two or three reasons or supporting facts
3. A brief wrap-up or what-happens-next

You don't announce this structure. You don't say "I have three points." You just follow it. And your speech instantly sounds more articulate and organized — because it actually is.

Mistake 5: Rushing Through Your Points

There's a specific kind of anxiety-driven speaking that I think of as "verbal running." It's when someone is so worried about losing their audience — or losing their own train of thought — that they pour words out as fast as physically possible, like they're trying to get everything said before someone interrupts or their brain shuts off.

I used to do this. Especially in meetings where I felt outranked. I'd get the floor and immediately floor the gas pedal, cramming as much content as possible into my allotted time. The result? Nobody absorbed anything. They heard a wall of sound and retained approximately none of it.

Speed undermines your message in two ways. First, your audience literally can't process information at the rate you're throwing it at them. Their brains need micro-pauses between ideas to file and comprehend. Eliminate those pauses, and comprehension nosedives. Second, speed signals nervousness, not confidence. A person who speaks slowly and deliberately reads as authoritative. A person who rattles off words at 200 words per minute reads as anxious — regardless of how brilliant the content is.

The sweet spot for important communication is 130–150 words per minute. Most nervous speakers hit 170–200 or higher. That gap is huge. And the irony is that slowing down actually makes you more persuasive, not less. You'd think saying less per minute would mean conveying less. But the opposite is true — your listener absorbs and retains more because each point has room to land.

Practical techniques that actually help:

• Breathe between sentences. Not a big dramatic breath. Just a normal one. It creates a natural pause and prevents your pace from running away.
• Lean into key words. When you put deliberate emphasis on important words, it naturally slows you down and gives those words more impact.
• Pause after your big points. Said something important? Stop talking for two seconds. Let it sink in. It'll feel eternal. Your audience won't even notice the gap.
• Do speed drills. Read a paragraph aloud in two minutes. Then read it again in two and a half minutes. Feel the difference? That's the pace you're aiming for.

If public speaking anxiety is what's driving the speed, you'll need to address both the symptom (rushing) and the cause (anxiety). They reinforce each other — rushing increases your sense of being out of control, which increases anxiety, which makes you rush more.

How to Fix These Habits

Here's what all five of these mistakes have in common: you're probably not aware you're doing them. That's not a character flaw — it's just how habits work. They live below the level of conscious awareness, which means the first and most important step is always the same: become aware.

Here's a four-week plan that actually works:

1. Week 1: Audit. Record yourself in three different speaking situations — a casual conversation, a meeting, and explaining something to someone. Listen back (cringe-inducing, I know) and honestly assess which of the five mistakes you make most. Don't try to fix anything yet. Just notice.
2. Week 2: Focus on one. Pick your worst offender. Just one. Every conversation, every meeting, try to catch yourself in that one habit and correct it. Don't try to overhaul your entire speaking style — you'll just freeze up and sound robotic.
3. Week 3: Stack a second. Keep working on the first habit while adding awareness of a second one. By now, the first fix is starting to feel more natural, so you have mental bandwidth for another focus area.
4. Week 4: Get feedback. Ask someone you trust — a friend, a colleague, a partner — "Hey, have you noticed anything different about how I've been communicating lately?" External feedback confirms what you're feeling internally and usually surfaces things you've missed.

Here's the thing that ties all of this together: many of these mistakes are actually compensating behaviors for underlying verbal fluency weaknesses. Hedging because you're not sure the right word will come. Rushing because you're afraid you'll lose your train of thought. Using big words because you don't trust simpler ones to convey authority.

When you strengthen your core verbal fluency through daily exercises, a lot of these surface-level habits start dissolving on their own. Words come faster, so you don't need to hedge or rush. Your vocabulary gets more precise, so you don't need to reach for impressive-sounding words. It's like fixing the foundation — a lot of the cracks in the walls close up naturally.