1. To vocalize one's criticisms of or arguments against someone or something. A number of former employees have banded together to speak against the immoral practices of the pharmaceutical company. The activist was jailed for speaking against the government. More and more people are speaking against the dangers of dependency on fossil fuels.

2. To represent or evince a very critical or negative portrait of or opinion against someone or something. The long wait times, high prices, and mediocre food all speak against the trendy new restaurant in my eyes. I think the sluggish growth in the economy really speaks against the government's burdensome policies.