don't rush while speaking as it might make it hard for others to understand what you said specially when the audience is from different countries and aren't used to your accent. speaking slowly also gives you time to think and filter as there are things which you should not reveal like company secrets, remember the formal setting of programming conversations?
over time you should develop your own unique speaking style. like mmeeks lowers down his voice around the end of the sentence or when mst takes pauses and talks in a plain sad tone about the writer bugs situation. thorsten raises his voice a little when he has to emphasise on something, like the hump in a camel case variable name, armin's classic "whatever, we will see"... this isn't easy, it requires quite some reading and awareness.