people who opposed imperialism

anti-imperialists

what can i write for a speech on people who opposed imperialism

Limit your subject to a particular time and a few places.

Tell who they were.
Why did they oppose imperialism?
What happened to their opposition?

ok thank you i will writing my response when i have it

Be sure you have a thesis statement and an outline before you start writing.

in a speech you still need a thesis?

Yes. Your audience still needs to know what to expect in your speech.