The Birthday Party thrives on language that often confuses rather than clarifies, fostering a sense of doubt and ambiguity. The dialogue reveals certain aspects only to contradict or render them illogical moments later, making it impossible to separate allegation from truth and fact from fiction. Even the simplest questions are enveloped in uncertainty—questions that should have clear answers. Is it really Stanley's birthday, as Meg claims, or is it not, as Stanley insists? Has Meg actually heard Stanley play the piano, or does his situation make that impossible? Is Stanley even a pianist at all?

Despite numerous details, the play frustratingly lacks concrete facts to confirm anything or adequately explain the characters' behavior. Brief moments of clarity quickly slip away like water down a drain. Most notably, the cause Stanley allegedly betrayed is never identified and remains as mysterious as Goldberg's sexual implements in his briefcase, the literalness of the Monty, or the exact nature of Stanley's impending fate.