The three most prominent theme in Mountain Language by Harold Pinter is that of meaninglessness. this meaninglessness hinges on the mountain language that they speak which has been outlawed. As they attempt to make logical sense and order out of their imprisonment, they are foiled at every attempt because there is no logic behind the rules they are made to follow. The meaninglessness that confronts them leads to isolation and anguish. Building this isolation, which is real and not just philosophical for the prisoners, is the disintegration of communication between the two language sides: nothing can be done because language breaks down to absurdities.
The themes of social protest and censorship stem from the disintegration of language. Scenes in which assistance or help is denied because language breaks down to absurdities constitute social protests at inhumane treatment and attitudes and artificially imposed limitation and restrictions. Incited by the language breakdowns comes censorship in the form of prohibitions against the mountain language being used for communication between prisoners. [This is not fantasy, of course, as such censorship is an integral part of many school systems where unintelligible dialects are spoken by local school children.]