That is why lecturing or presenting in front of a professional audience is one of the most common tasks for a researcher, in addition to publishing of course.
Not everyone is born to be a charismatic speaker. Most of us have heard lectures that use monotonous melodies, insecure non-verbal behaviour or poorly designed slides that distract from the lecture itself. The audience might not always be willing to dedicate attention to the scientific content of the lecture when voice, body-language and presentation skills do not meet professional standards.
Presenter’s authenticity, a logical structure, and the focus on only a few key messages are key to a convincing presentation. The more you can inspire your audience the less you torture them and the more competent you appear.