Design language system

I hope this is relevant to UX as most articles about DLS`s are written by UX designers.

I read many articles about it but couldn`t find any mentions about:

  1. Who is responsible with creating a DLS ( an UX designer , a team composed of who ? )
  2. What software is best to be used to mantain a DLS ?

I would appreciate any personal experiences that you had with a design language system, as I am asked to create one all by myself and find it way to complex to wrap my head around it.