When we're nervous giving a speech, we often speak too fast. Slow yourself down by pausing on the vowels.
Over at Ragan, they've got some tips on remembering to slow down. Use vowels as a pacing cue:
This is a common technique for non-English speakers with heavy accents; stretching your vowels can help slow you down and keep you focused. Imagine that the vowels are italicized as you speak, and take time to pronounce them clearly. Use this technique as you practice, but make sure that you sound natural during the presentation by asking a friend to listen.
Click the link for other ways to slow yourself down when speaking in public.
How to slow down nervous, speedy speech | Ragan.com
Photo by Maryland GovPics.