When you decide on topic, you may need some background information to help you decide how to focus the topic of your speech, or to help you decide what you even need to know to do research on your topic.
Wikipedia and Google searches are great for this - if your topic has a Wikipedia page or has been discussed widely enough on the Internet to show up in Google search results.
As you do your research using Google and Wikipedia, keep in mind that the while contributing to the web is certainly more democratic than on legacy media platforms, there are still significant limitations to access that mean that information online is not necessarily representative of the world at large. For example, Wikipedia is considered to have significant gender and racial bias in terms of coverage and language used.
In addition to searching the open web, you may also want to try the following library-based research tools. All of these tools offer accessible overviews of topics and links to further resources.