I think Speak Up : used to ask someone to speak louder. EX : Could you speak up, please? Speak Out : to publicly speak in protest about something, especially when protesting could be dangerous. EX : students who had spoken out against the regime were arrested.

Speaking up is also when you speak out about something you care a lot about.

Check out this updated version...please feel free to share if you enjoyed it. https://www.linkedin.com/pulse/20141004202226-16432482-when-should-customers-speak-up-and-or-speak-out/?published=t When Should Customers Speak Up and/or Speak Out? Is there a difference?