intransitive verb
1. : to speak strongly or vigorously — usually used with for
speak up for truth and justice — Clive Bell
2. : to speak loudly and distinctly
was told to speak up as the people … could not hear him — B.L.K.Henderson
3. : to express an opinion freely and fearlessly
we'll never find out how we feel about one another if we don't speak up — D.B.Chidsey