Impromptu speeches are a great way to hone your speaking skills. It requires the ability to formulate your thoughts, and deliver them in a semi cohesive manner while everyone is watching and critiquing. It all happens at the same time and can be particularly unnerving. The good news is that once you become comfortable doing that, you can continue giving off-the-cuff speeches about a myriad of topics. So take every unexpected opportunity to speak, because by doing so, you will develop a worthwhile skill.