How People Lie Through Grammar
Once you see these tells in action, you'll never get caught by them again.
We’re taught to look for lies in what people say, and some folks are better than others at seeing them. But trained profilers and interrogators know the deeper signal is in how someone says something. Deception analysis looks at a more holistic view. Shifts in tense, dropped pronouns, or oddly structured timelines often expose the gap between what someone wants you to believe and what actually happened.
When someone is lying, their brain has to do multiple things at once: fabricate a story, monitor your reaction, and manage their own anxiety. That overload causes micro-slips in language, and the subject of time is one of the first places that the brain trips up.
Your brain knows what it knows. It stores not just facts, but context—where you’ve been, what you’ve said, who you saw, and how you felt about it. It doesn’t hold onto every detail forever, but it organizes and prioritizes information based on emotional weight, relevance, and survival utility.
Here’s the problem for liars: the brain isn’t built for omission. It’s designed for pattern completion.
And most lying is done through omission, not outright fabrication. It’s easier and emotionally safer because for many, leaving out a piece doesn’t seem as bad as outright fabricating a story.
Omission, however, creates friction because your brain doesn’t forget the parts you leave out. When someone deliberately omits part of a story, their brain still wants to fill in the missing details. It knows what was supposed to be there. And that’s where the leakage happens—grammatical slippage, pronoun shifts, or tense errors. These are the tells. Not because the person is stupid or nervous, but because omission short-circuits the brain’s storytelling system. The lie may be deliberate, but the grammar is automatic. The brain cannot help but act as if the missing info is still there, because it remembers the info even if you left it out.
Let’s break down the tells that show up in grammar, and how you can spot them. First, however, let’s set some ground rules.
These are not a smoking gun. Don’t immediately jump on someone and accuse them of lying if you hear these tells. They’re signs that you need to investigate more, because there is absolutely something in the gap. It does NOT always mean that they are lying about their story. It might mean that they are covering for an emotional need or other deeply personal fear. You need to figure out what the ‘something’ is that they are hiding so that you can address it appropriately.
You must start with absolute belief in their truthfulness. This sounds wonky, right? I’m trying to see if they’re lying so why would I give them the benefit of the doubt? As an instructor once told me, “Starting from the assumption that they are lying and you just need to find it means you will never miss a liar, but you will miss a truth-teller.” Start out with the assumption that they are telling the truth, and that for you to change your opinion means they gave you undeniable, repeated evidence that they are being deceptive and why. There is never just one sign of deception. There are always multiples.
Each of us has a dictionary in our brain. We specifically use certain words because the brain assigns a definition to it based on the context that it recognizes. For instance, when telling a story about getting pulled over, you might refer to your car five different times, but then when recounting what the officer said, you suddenly refer to it as your ‘vehicle’. Your brain noted the context change, and chose a different word for it. Change in language means change in perception. To recognize deception, you need to know their dictionary.
There are many other rules, but these few will get us started for today. Let’s get into it.
1. Past Tense vs. Present Tense
Truthful people usually talk about past events in the past tense. Liars often slip into present tense because they’re "seeing" the event in their head as they invent it.
Truthful: "I walked into the store and grabbed a drink."
Deceptive: "I walk in, and the guy’s just standing there, and I’m like..."
The shift to present tense is a red flag, especially if it shifts in the middle of a story. It signals that something has changed in their brain in terms of perception of the situation. They may be leaving something out, exaggerating, or inserting.
2. Timeline Distortion
Liars struggle with sequential events. They often skip time references or blur transitions. These are called temporal lacunae, and it’s a telltale sign that not only do you need to dig deeper, but it tells you exactly where to dig.
Watch for:
"Next thing I know..."
"And then somehow..."
"Suddenly..."
“Later…”
These phrases often patch over gaps in narrative. They replace a linear timeline with fuzziness, and let you know there’s a hole in the path. Don’t jump over the hole; climb in and see what’s there.
3. Passive Voice
Liars will often unconsciously shift into passive voice to avoid owning an action.
Deceptive: "The gun went off."
Truthful: "I pulled the trigger."
If someone consistently avoids first-person subjects in key moments, they may be distancing themselves from responsibility. Look for whether they are assigning the agency to an inanimate object or even a word. Have you ever tripped on the sidewalk and then turned around to see why the sidewalk tripped you? That’s exactly the principle I’m talking about.
Side note: You see this a lot in abusive group dynamics or relationships. Someone might say, “Sorry, that [verbally abusive thing] just flew out of my mouth.” This is not ownership; instead, it uses passive language to assign agency to the thing that was said. A real apology would own, accept responsibility, and feel remorse.
“I am sorry that I said that. It was wrong, and I hurt you. Will you forgive me?”
When was the last time you heard that kind of ownership in your group, by the way?
4. Improper Past Perfect Tense
Sometimes liars overcompensate and try to sound precise. They’ll use past perfect tense where it doesn’t belong, and they’ll use it repeatedly, especially to overbuild context:
Deceptive: "I had gone to the store, and I had seen him there. I hadn’t expected to see him, but I also hadn’t seen his car and so I hadn’t realized he was there."
Truthful: "I drove by the store to see if he was there and when I saw his car I stopped in."
Overuse of "had" often signals a rehearsed story or an attempt to sound formal or accurate, which ironically works against them.
5. Shifts in Pronoun Use: Dropping the "I"
Truthful people use first-person pronouns naturally. Liars often drop them at key moments when they don’t want to put themselves in a position of owning an action.
Deceptive: "Went to the house, found the door open."
Truthful: "I went to the house and found the door open."
The pronoun “I” denotes ownership, so if you don’t see it, they’re not owning the action or thought. When they’re at a point where ownership is necessary but they aren’t doing it, that’s a sign. Dropping the "I" creates distance. It’s a subtle way to deflect personal connection to the events.
Liars don’t just say untrue things. They say them differently. Tense, timeline, and pronouns all shift under the weight.
If you want to detect deception, stop listening only to the story. Listen to the structure. The truth lives in the grammar.
📄 Transcript Excerpt (Deceptive Statement)
"So I’m walking up to the house, and like... the door’s kind of open. I push it, and there’s blood everywhere."
This looks like a shady statement on its face, sure, but can you put your finger on why? Let’s break it down.
Statement Analysis with Behavioral Flags
1. Present Tense for a Past Event
"I’m walking..." / "I push it..."
Indicates storytelling, not memory. The event happened in the past, but the subject frames it as if it’s occurring now.
Profiler Note: Liars often default to present tense because they are constructing imagery in real-time.
2. Disassociation via Filler Phrases
"...and like..."
Linguistic hedging. Introduces distance between speaker and content.
Profiler Note: Often appears before a distortion or psychological discomfort. Double-check, however, if the person routinely uses this as a filler. If they’re using it multiple times a sentence, that’s one thing. If they only use it specifically at certain times, that’s a clue.
3. Passive Emotional Response
"There’s blood everywhere" — but no emotional reaction is stated.
Profiler Note: A truthful person encountering an overwhelming scene usually includes a visceral reaction—"I freaked out," "I froze," "I didn’t know what to do" because the brain encodes not just what was seen, but the associated physiological and emotional response. That reaction becomes part of the memory trace.
This is also why the hippocampus, when later triggered by a similar stimulus, can reactivate the same emotional state. That’s what we refer to clinically as a trigger—a stored somatic/emotional memory resurfacing involuntarily.
When that kind of reaction is missing from an account—especially in a high-impact moment—it may suggest a controlled, constructed narrative rather than a relived memory.
Alternatively, it may indicate trauma-induced dissociation. In those cases, the emotional system shuts down or disconnects entirely in the moment of overwhelm. If you are quick to judge deception, you risk accusing someone falsely. Both patterns warrant deeper analysis; while only one is active deception, you want to know if either thing is occurring.
4. Timeline Collapse
Sequence goes from house approach to blood discovery in 11 words. No transitions, no sensory buildup, no internal reaction.
Profiler Note: This compression often conceals either guilt or complicity. Time gaps are collapsed to avoid critical details.
5. No Preceding Action or Context
Missing details about why he went to the house, how he got there, or what time.
Profiler Note: Deceptive subjects often skip context to focus on the moment they also want YOU to focus on. It’s something like, “never mind that I pulled all of your strawberry plants out of the ground; please focus on the strawberry pie I made you.”
These are just the grammatical tells. There are more, and we’ll get to those in a future article.
5 Questions for a Quick Once-Over Analysis
Ask yourself:
Is the timeline continuous, or are there jump cuts?
Does the speaker show emotion, or just describe facts?
Are reactions missing where they should be?
Do you hear linguistic distancing, such as "the" vs. "my," or passive voice?
Does the speaker seem rehearsed or emotionally flat?
Again, these aren’t smoking guns; proper analysis requires time, diligence, and patience. But they will give you a quick sense of where to go next in your vetting.
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