There are a variety of source types that you may encounter when researching for your speeches. The differences between source types varies such as the depth of topic coverage, intended audience (e.g. academic, general), and purpose.
What kind of information do you need?
Latest information on a current event?
Historical information on a past event?
Current research on a topic or issue?
Opposing perspectives for an argument?
Overview on a topic?
Reminder: Always review the speech assignment for any source requirements (e.g. age of source, type of source).