4. They are saying too much
On the other side, a study conducted by researchers from Harvard Business School showed that liars tend to stretch their version of “truth” with too many words. Moreover, someone who’s lying may make up things as they go, which usually implies adding excessive detail.
The reason they do that is because they are trying to convince both themselves and others of what they’re saying. Liars may also embellish their speech with words that a truth-teller wouldn’t think of adding.
Other linguistic signs revealed in this study indicate that deceivers tend to swear more and use third-person pronouns (like “she,” “he,” and “they”) instead of pronouns like “I,” “my,” or “mine” to distance themselves from any first-person involvement.