idea, for a particular audience (more on this below), is essential in crafting powerful and engaging speech and writing. The repetition of the same words over and over again quickly bores people, while the skilled use of a wide array of them enables you to draw people in and paint a rich picture. This is why an expansive vocabulary is one of the keys for great leaders -- words allow you to grab the interest, and then allegiance, of others. And a robust vocabulary is just as important when you're operating off the cuff as when your remarks are pre-planned -- instead of hemming and hawing, searching for the right words to say, you can express yourself forcefully and with confidence. Boosts your powers of persuasion. It's hard to get people interested in an idea -- whether a tangible product, a business pitch, or a piece of philosophy -- and convince them of it unless you 1) understand it inside and out yourself, and 2) can describe it to others in an engaging way (see the two points above). Repeating the same word over and over again ("I've got this cool idea. See, it's got this cool wheel here and then this really cool axle stick outs...") is going to have the eyes of your audience quickly glazing over. It certainly won't help you sell them on something, or on yourself -- issuing banalities in a job interview ("I'm a hard worker and a people person!") won't do anything to