Often it's the delivery which causes the audience to smile, so speak slowly and remember that a raised eyebrow or an unbelieving look may help to show that you are making a light-hearted remark.
The first is called ignoring and it's just downright rude, so the second level is the kind of level my sister talks to to my mom, it's called pretending.
No matter whether you're introducing yourself, telling a story or saying, " Thank you, " to someone who held the door for you, do it in a full and clear voice.
You've probably been in a situation where the presenter is not very well organized, and then it just becomes difficult to to listen to this presentation, or to sit through the presentation that this person is giving.
Back to Joseph Priestley, whose rudiments of English grammar insists that the custom of speaking is the original and only just standard of any language.
The short answer: new accents begin to develop when isolated groups of speakers start making nearly imperceptible changes to the way they pronounce words.
So far, Alice had been very small, then very tall, then very small again in this strange Wonderland she found when she chased a talking rabbit and fell down the rabbit hole.