disempower is the opposite of empower. Empower means: allow and suggest that they have the power. Provide them with what they need to have the power.
Disempower is taking away what you already have.
What people consider as negative self-talk or negativity is in essence disempowering talk. You have the power, innately, to do the things that your heart says you can do.
You are never given a desire that you are not equipped to fulfill... so in essence, if you don't fulfill on your desires, it means that either your self-talk or the talk of another disempowered you: you allowed some talk convince you that you can't.