The importance of a theme is something I state often.
As my good friend, NCFCA TP Champion and coach, Rebecca Frazer said, "Good communication is practically always thematic. Your favorite movies are your favorite movies because they leave you with strong, central feelings. Every round strategy–aff or neg–must be centered around a strong theme. Stating a value in a case does not make it thematic, nor does stating a negative philosophy. Some of the best values I have ever seen in debate are so obvious that they don’t even need to be labeled–every argument the team makes ties back to a clear idea that they value. Please don’t let your judge leave the debate round wondering, “Hmm, so I wonder what was really important to them?”
The same is true for Speech. You want your audience to remember you- as well as what you have said, or performed. How?! This can be done by having a theme! A theme can be an underlying topic or recurring idea in your speech. Your memory is powered by your brain, which is full of emotions. Those emotions can be triggered by impacting the audience through a theme. Think about it- a judge will listen to 8 students give a speech for 10 minutes each... That's 80 minutes of speeches! You want to be sure they remember you! How can that be done?