Gee

“All of us acquire at least one initial discourse”

The initial discourse is how you first familiarize with the world. Usually this is our families or schoolmates in elementary school.

“Dominant groups often apply constant ‘tests’ of fluency in specific discourses”

This makes sense as people generally hate it when people pretend to know of something they don’t. I hate it when people talk about something and get everything wrong. “Halo is about a robot that fights aliens and saves people” No, he is not a robot, he is human.

“Not all discourses involve reading or writing”

This is very true. Discourse communities can be anywhere. They could involve anything that groups of people could talk about. There are communities that play video games, in which case would involve little writing and little reading. Same would happen with sports teams or fishermen and the like.

“Mushfaking has to do with something lesser when the real thing is unavailable.”

People do this all the time. I remember in grade school using the lid to a pudding cup as a spoon because I couldn’t get a real one due to my excessive laziness at the time. Sometimes in communities you have to do this in order to make due with what you have. Like in the discourse community of Machinima (using video games to make movies) you have to make do with the tools the developer gives you, which is why Halo is a popular machinima platform because of its theater mode which was born from the popular machinima “Red vs Blue”.  The creator used to just sit there with a character that wasn’t holding a weapon to make it look like an actual camera, which once theater mode was introduced into Halo 3, was no longer an issue.