To me what stands out is not the fact that men speak up more than women do, but that women get ignored/dismissed when they do speak. I make an effort to:
Give them attention
Understand their point of view
Engage in their point of view
Not let others (men) interrupt and if they do, quickly get back to the core discussion until the speaker is satisfied/has said everything they wanted to say
Basically give your attention not to the loudest ones, but the ones that deserve it. Things like these make all people who usually don’t engage in discussions more likely to engage in the future.