I have similar requirement as Shirley. I'm looking to achieve a custom taxonomy / naming convention
The naming convention used in my case is 'Capabilities' which is a combination of 3 components to achieve an outcome: knowledge, process and skills. Questioning and listening is one capability defined below.
The scale for competency is as follows.
Personally, I think capability is what you do and competency is how well you do it i.e. the scale. This could be worked round if there were the ability to customise the exiting predefined taxonomy list.