Two plays by Tom Stoppard. Or one play: part of the second makes no sense unless it is performed straight after the first.

Dogg's Hamlet is... oh god, how do I describe this? (A common problem summarizing Stoppard.) It is a school speech day, and after the prize-giving there will be 15-minute performance of Hamlet. (Followed by a one-minute reprise of the whole thing.) But before that, the platform has to be set up. It is to be built out of blocks, slabs, planks, and cubes. A workman arrives to do this, and is watched by some of the schoolboys.

Near the beginning of Philosophical Investigations, Wittgenstein considers that utterances are given meaning by context. If one builder calls out "plank" and another builder hands him a plank, we tend to think of it as a reduced form of a longer, syntactically complex sentence such as "Give me a plank". But Wittgenstein considers a simple language consisting only of utterances like "plank" and "block", which result in an action. You can not then say that the word means specifically the noun, the thing, or is a verb, a command. The context does not require a distinction. If the builders know what order the pieces come in, "plank" might just mean "ready" or "next".

Okay. The builder speaks English, and says "cube" and "plank" and so on for the things in his lorry. But the schoolboys speak Dogg, where every single word is an English word but with an entirely unrelated meaning. So they test the microphone with Breakfast, breakfast... sun -- dock -- trog, they call each other vanilla squire when angry, and politely ask the time of a stranger with cretinous pig-faced, git?

The conversation of the workman and the children goes on simultaneously in both languages for a long time and becomes very intricate. Because of their actions on stage, you can understand the import of it all. This extends to the football scores on the radio, Dogg the headmaster's speech, and the lady guest of honour's very gracious speech (beginning "Sad fact, brats pule puke crap-pot stink, spit; grow up dunces crooks; rank socks dank snotrags...).

Cahoot's Macbeth is about an underground performance of Macbeth in Communist Czechoslovakia. Various intellectuals who have been deprived of their freedom of speech gather in a private house to act out this tale of tyranny and evil. A comical secret service agent enters and tries to disrupt and intimidate them. Then the builder from Dogg's Hamlet turns up to make a delivery, only this time he's the one speaking Dogg. Gradually the Czech actors pick it up and realize they can't be censored if they act Shakespeare in Dogg.

The first half was created for The Dogg's Troupe of Inter-Action, who performed the 15-minute Hamlet on a double-decker bus, and did the other bit called Dogg's Our Pet in Soho in December 1971. The second half is based on the real-life underground performances of the banned Czech playwright Pavel Kohout, whom Stoppard met in Prague in 1977. The full combined performance was first given on 21 May 1979 in Coventry.

Interesting, Václav Havel had a 1980 play The Memorandum involving a constructed language, so I presume he was paying tribute to his fellow playwright's ideas.