We work all the time with people who want to improve their speaking skills. But like any coaching situation, you need to determine what the root cause of the speaking problem is, before you can solve for or eliminate the problem.
Does the speaking problem manifest itself with poor delivery and little projected confidence? Well, if so, the solution to the problem is not to work on delivery, and confidence. These manifestations are likely signs of a deeper problem that must be addressed.
For example, the problem could be caused by poor practice habits. The speaker may not be practicing, out loud, nearly enough. Or, we could dig deeper. More fundamentally, the speaker may not be preparing well. He or she may not have a clear goal, or may not be researching the audience well, or may not be outlining the key messages so that they are simple and easy to follow. All of these problems could be causing the poor delivery and lack of confidence, because sub-consciously, the speaker knows when they have the story organized sufficiently. And when they do not have it organized, their delivery suffers and confidence goes down.
Even more fundamentally, if the preparation is lacking, especially the audience preparation, the root problem may be that the speaker is not listening well enough. Good listening skills help us speak better in so many ways. When we listen well, we are more prepared, we know more about our audience, and we are better able to react to things that may come up.
So if you see a problem with the way someone is speaking or presenting in the work place, the solution may not be so obvious. A little root cause analysis can help get to the heart of the issue, so that the REAL problem gets addressed.
Good luck, and have a great day.