1. Seek out honest feedback. As with trying to change any behavior, the first step is to become aware of it. In her coaching sessions, Jahnke usually starts by videotaping a client talking and reviewing it with the client. "People are usually surprised when they watch and hear themselves," she says. "Most of us don't really know how we're coming across."
A trusted friend or coworker may be able to offer suggestions, or your company's human resources department may even provide a few professional coaching sessions -- especially for high-potential types like your teammate.
1. Join Toastmasters International. With 13,000 chapters in 16 countries, Toastmasters probably has a club near you. "It is a great organization, full of people who are seriously trying to improve their speaking skills in a friendly, collegial atmosphere," Jahnke says. "And it's free."
3. Study the speaking styles of successful people. "Women have so many more role models now than ever before, so it's easy to find executives whose speaking styles have helped to get them where they are today," notes Jahnke. She recommends checking out TED.com, which offers thousands of 20-minute talks by interesting people.
"Look up Sheryl Sandberg at Facebook, or Melinda Gates," Jahnke suggests. "Or find YouTube videos of [Pepsico CEO] Indra Nooyi. Notice how they pace their speech, and how they use pauses. With some effort and practice, these are things anyone can learn."
4. Take note of how higher-ups at your company express their ideas. Naturally, communication styles vary somewhat from one corporate culture to another, so it makes sense to pay attention to how people above you talk. "If there is someone who is particularly effective at getting his or her ideas across, you might emulate the way they do it," says Jahnke.
"The idea is not to parrot someone else's speech patterns, but to adopt the elements of their style that you can comfortably learn to use," she adds. "In the end, it's still about expressing yourself and your unique ideas -- but your best self, presented in a way that will make others listen."
Talkback: Do you agree that the way someone speaks can make or break a career? What habits of speech do you find distracting or unprofessional? Leave a comment below.