be not so broad or so narrow that you can't find relevant resources. In my experience, students tend to have lots of good ideas for topics, but they are initially too big; the kind of topic you could write a whole book about. For a short speech, you need a topic you can address in your limited time.
DACA should be renewed as part of an immigration overhaul
People with domestic violence charges should not be allowed access to guns
Funding for school lunch programs should be increased to enable schools to offer more healthful food choices
Describe how a specific type of therapy animal supports those with a specific health concern
Health care for veterans
Funding for PTSD programs should be increased
How a focused research topic influences your search process
This video from a library in Canada demonstrates how narrowing your research topic can change your research process and make it eaiser to find sources that are relevant to what you want to discuss.