Sometimes, we have a tendency to speak faster or trip over our words when we are nervous, so make sure you warm up before you speak in public. Tongue-twisters are great for enunciation and relaxing tension in your face. Plus, let's be honest: they are really fun to do.
Get started with a (deceptively) simple one: repeatedly say 'red lorry yellow lorry' as fast as you can . . . not so easy, is it? If you need more inspiration, ask a Siri or Alexa-enabled device to tell you a tongue-twister.