How can I get the opportunity to talk during my meetings with professors? I am a PhD student and often I will meet with my advisor and our collaborators.  But they always do all the talking even though I am the only one writing code.  And sometimes I will try to ask a question or make a suggestion and then half the time they will just talk over me.

I am wondering if this is because I am a woman, or because I am the only PhD student in the meeting, or if I am just not talking loud enough or something.  I am also wondering if this would keep happening to me if I quit my PhD and worked at a male dominated software company, or if it is more specific to academia, and made worse by the fact that everyone I interact with is much more senior than me.

I have another project where both my collaborators are women and this never happens when I work with them.
Why not write an email to your advisor with your concerns?

Women are not the only ones with this problem.  Those fast-talkers maybe don't even realize they are leaving you out.  

Here is a good book.
Quiet: The Power of Introverts in a World That Can't Stop Talking,
by Susan Cain
It may help you understand your situation.  But it's those other guys who need to read it, and probably won't.

When you get to a software company, it may get better.  At least if it is large enough to have managers who are not merely former programmers who were promoted.  One can hope that those with management training know about these things: The one with the loudest voice may not be the one with the best idea.  And there are management practices that can make the best of all workers, whether they are fast-talkers or timid wall-flowers.