If you want to unspecify a shader in a program (that is, no longer use it), just give its vertex, fragment, tessellation, or geometry command with no arguments.

The next day I couldn't use my black pair to school and in order not to spoil my white pair I used my bakias or wooden clogs instead. As I clomped into the classroom, for I was late that morning, my school teacher—a German nun—looked up and I saw her face wrinkle with displeasure, […]

You're right that it's not the primary concern of the artlanger, but you might be surprised to learn that many artlangers have considered what their conlangs sound like to the extent of making recordings of texts and learning to speak others' conlangs.

A newsgroup about abortion is far more trollable than one about linguistics.