dumb down

verb2

1. •
   To convey some subject matter in simple terms, avoiding technical or academic language, especially in a way that is considered condescending.

   • The public won't understand this concept. We need to dumb down our explanation of it.
2. •
   To become simpler in expression or content; to become unacceptably simplistic.

   • Television has really dumbed down over the past ten years.