Watch this video of Jane Goodall. Notice how she speaks confidently about her abilities and expertise (3:06) but is also willing to admit when she isn’t comfortable with a particular topic (4:55 – 5:20).
Watch how Janina Benyus builds up her audience in this speech. Between 7:27 and 7:51, she acknowledges who her audience is and subtly praises them for their advancements in the field she’s discussing.