Lexical Diversity
Description: Lexical diversity is a term used among interpersonal communication scholars to describe the range of a speaker's vocabulary. As an example, a speaker who only uses the term "approach" throughout a speech is not considered as lexically diverse as one who uses "approach," "strategy," "plan," and "program." She who uses "approve" four times is not as diverse as she who uses "approve," "permit," "sanction," and "authorize" once apiece.
Why It Matters: Research demonstrates that audiences consistently judge lexically diverse speakers as more competent, of higher social status, and more persuasive than a low-diversity counterpart. The effect is stronger still the more formal the situation, and it doesn't lie only among spoken communication: lexically diverse written messages demonstrate the same positive effects as well, and often to a greater extent.
The Coaching Point: Break out the thesaurus. While it's possible (and often easy) to take the range of vocabulary too far and appear pretentious, as a general rule important communications--especially those in formal social situations or those that are written--will benefit from favoring a solid range of well-understood synonyms over otherwise common-place language.