Who's the smartest CEO? How Bezos, Buffett, Musk and Zuckerberg rank

What's in a word? A CEO's level of intelligence, according to a new analysis of dialogue from e-learning platform, Preply. 

The study, which evaluated the linguistic patterns of 100 U.S. executives, identified who tops the smart scale based on their speech — and who is successful thanks to other important leadership traits. 

When it comes to the use of vocabulary, critical thinking and relevance in their public appearances, chief execs from DeepMind, Blackstone Group and Berkshire Hathaway were ranked highest in terms of intellect — while Tesla CEO Elon Musk came in at number 16. Having a highly intelligent person in the CEO's seat benefits not only the business, but its people as well, says Sylvia Johnson, language expert and head of methodology at Preply.

"A highly intelligent leader has a clear vision, goals and method for bringing a business to fruition," she says. "Leaders who are highly intelligent also bring loyalty and dedication to the workforce. Lastly, leaders who are classified as highly intelligent are not afraid to be creative and think outside of the box." 

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Along with intellectual intelligence, Johnson points out that a leader's level of emotional intelligence can be a key factor in making their communication more effective. In this category, Progressive CEO Tricia Griffith took the top spot, Goldman Sachs CEO David Solomon came in second; Warren Buffett, Mark Zuckerberg and Musk all made the top 10, while Bumble's Whitney Herd and Square's Jack Dorsey earned spots in the top 20. 

"When it comes to leadership, one of the most important qualities is to be able to communicate with employees in a way that shows understanding and empathy," Johnson says. "At times, those who are highly intelligent can show a lack of humility, a lack of self-awareness or even excess sophistication in explaining tasks — all of which separate them from the very people helping bring their vision to life. That is why emotional intelligence and being able to take ownership for one's shortcomings, along with being highly intelligent, is what makes an effective leader."

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For leaders wondering how to improve their skills in these categories, Johnson says working to develop more customer-centric and team-focused approaches are great areas to start.

"Learn more, study more," she says. "Learning to be more empathetic and admitting when [you're] wrong — these are traits that can help leaders become more emotionally intelligent and positive. When it comes to focusing on the external, the most important thing is to genuinely be excited about hearing from others, learning from them and helping them grow. Effective leadership does not happen in a silo — it has to be enacted with the people you want to work with." Here are the 10 CEOs who made Preply's list of most intelligent executives.