How is employee VOICE in the workplace different from SATISFACTION or  ENGAGEMENT?  Well, it's more frequent, measures more than engagement or  satisfaction (although it might do that too), and it may be diagnostic.     

I spoke with Rob Catalano who started and runs WorkTango which is a tool  to help their customers understand the perspective of their employees.   Employee voice can be used to understand the sentiment of employees in  general but also in response to particular initiatives or changes.  For  example, it could help measure the effectiveness of diversity, equity  and inclusion programs.  And, if shared with leaders, can help them  respond quickly to the feedback of their own employees.

worktango.com