The question—words or actions?—is a false choice.
Change can and does emerge through dialogue, debate, deliberation, diplomacy, and other modes of talk, but language is not enough on its own.
Power can be exercised—and opposed—through direct action, such as described in Gene Sharp’s approach to nonviolent action.
Sharp described how persuasion can change minds but persuasion isn’t the only, or even most frequently used, way nonviolent action contributes to change.
More often, nonviolent direct action disrupts an opponent’s ability to act, such as denying them a labor force through a strike, which forces the opponent to change their actions without necessarily changing their minds.
Direct action can also create a space for new conversation, opening paths for imagining futures other than the status quo.
And yet speech on its own is also not without power. If speech were totally without threat to authority, then authority would not expend so many resources to shut it down or distort it beyond its ability to help us transform our world.